1、Pathways to Innovation and Discovery in Particle PhysicsDraft for Approval 1 December 2023Particle Physics Project Prioritization PanelHigh Energy Physics Advisory PanelDecember 7,2023ExploringtheQuantumUniverseDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle Phy

2、sicsDRAFT Report of the 2023 Particle Physics Project Prioritization PanelDRAFT Report of the 2023 Particle Physics Project Prioritization PanelPreface iiiNow more than ever,particle physics is an international,even global,endeavor.The experiments needed to address the most profound questions of our

3、 field often require resources and cooperation at a global scale and can take more than a decade to design and build.We found the scope of our charge and the responsibility it represent-ed humbling.Throughout our deliberations,we were aware that the impact of our recommendations would be felt past t

4、he end of the next decade and beyond the borders of the US particle physics program.The recommended program reflects the consensus of the panel.The previous 2014 P5 report laid the foundations for the current particle physics program.Embracing its recommendations has positioned the US as a leader an

5、d strong international partner in efforts that encompass neutrino and flavor physics,the study of dark matter and cosmic evolution,and collider experiments.The community stands on the threshold of realizing the enormous scientific potential of that program.At the same time,the community-driven plann

6、ing process organized by the Division of Particles and Fields of the American Physical Society produced a spectrum of exciting new ideas for the future.We thank the particle physics community membersin the US and abroadfor their dedication and thoughtful input,not only through the community planning

7、 process,but through numerous town halls,talks,and private communications.The enthusiasm and engagement of early career participants,both in the planning process and in recent town halls,has been truly inspiring.They are the future leaders who will bring to life the goals and aspirations outlined in

8、 this report.We strove to carefully craft a balanced program in terms of scientific focus,project timescales,and the interplay between ongoing initiatives and the innovation essential for the future.Adhering to fiscal constraints means that not every ambitious endeavor can be immediately realized.Ag

9、ile,adaptable,and forward-looking projects are essential to the balance.Sustained progress over the next decade requires enhanced investment in research,theoretical frameworks,critical infrastructure,and emerging technologies.Also crucial is the commitment to build a respectful and inclusive communi

10、ty.We hope the resulting program enables early career researchers to spearhead progress and shape the future.We are excited to present this vision for US particle physics,one that builds on recent investments and successes,while opening pathways to innovation and discovery in the quest to explore th

11、e quantum universe.Respectfully submitted,2023 Particle Physics Project Prioritization PanelDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle Physics2023 Particle Physics Project Prioritization Panel in Denver,August 2023.Photo:Rowena SmithDRAFT Report of the 2023

12、 Particle Physics Project Prioritization PanelShoji AsaiUniversity of TokyoAmalia BallarinoCERNTulika BoseUniversity of Wisconsin-MadisonKyle CranmerUniversity of Wisconsin-MadisonFrancis-Yan Cyr-RacineUniversity of New MexicoSarah DemersYale UniversityCameron GeddesLawrence Berkeley National Labora

13、toryYuri GershteinRutgers UniversityKarsten Heeger,Deputy ChairYale UniversityBeate HeinemannDESYJoAnne Hewett,HEPAP chair,ex officio until May 2023SLAC National Accelerator LaboratoryPatrick HuberVirginia TechKendall MahnMichigan State UniversityRachel MandelbaumCarnegie Mellon UniversityJelena Mar

14、icicUniversity of Hawaii at ManoaPetra MerkelFermi National Accelerator LaboratoryChristopher MonahanWilliam&MaryHitoshi Murayama,ChairUniversity of California,BerkeleyPeter OnyisiUniversity of Texas at AustinMark PalmerBrookhaven National LaboratoryTor RaubenheimerSLAC National Accelerator Laborato

15、ry/Stanford UniversityMayly SanchezFlorida State UniversityRichard SchneeSouth Dakota School of Mines&TechnologySally Seidel,interim HEPAP chair,ex officio since June 2023University of New MexicoSeon-Hee SeoIBS Center for Underground Physics,Fermi National Accelerator LaboratoryJesse ThalerMassachus

16、etts Institute of TechnologyChristos TouramanisUniversity of LiverpoolAbigail ViereggUniversity of ChicagoAmanda WeinsteinIowa State UniversityLindley WinslowMassachusetts Institute of TechnologyTien-Tien YuUniversity of OregonRobert ZwaskaFermi National Accelerator LaboratoryPanel Members vDRAFT Ex

17、ploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization PanelTable of Contents viiDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle Physics iii Preface v Panel Members ix

18、 Executive Summary 1 1:Introduction 15 2:The Recommended Particle Physics Program 30 3:Decipher the Quantum Realm 46 4:Illuminate the Hidden Universe 62 5:Explore New Paradigms in Physics 77 6:Investing in the Future of Science and Technology 103 7:Technologically Advanced Workforce for Particle Phy

19、sics and the Nation 109 8:Budgetary Considerations 115 Appendix 141 Full List of Recommendations 148 AcknowledgementsEditingJames DawsonCopy EditingMarty HannaArt direction,design and developmentSandbox Studio,ChicagoMural IllustrationOlena ShmahaloSpot illustrationsAbigail MalateDRAFT Report of the

20、 2023 Particle Physics Project Prioritization PanelParticle physics studies the smallest constituents of our vast and complex universe.At such small scales,the fundamental principles of quantum physics prevail.Remarkably,the entire observable uni-verse,now billions of light years across,was once sma

21、ll enough to be quantum in nature.Its quantum history is imprinted on its large-scale structure.Past successes in particle physics have revolutionized our understanding of the universe and prompted a new set of questions.Collectively,these questions have spurred the construction of state-of-the-art

22、facilities,from particle accelerators to telescopes,that will illuminate the profound connections between the very small and the very large.We stand on the threshold of harnessing their full potential.The 2023 Particle Physics Project Prioritization Panel(P5)was charged with devel-oping a 10-year st

23、rategic plan for US particle physics,in the context of a 20-year global strategy and two constrained budget scenarios.An essential source of input was the 2021 Snowmass Community Planning Exercise organized by the Division of Particles and Fields of the American Physical Society.The panel received a

24、dditional input from several channels,including town hall meetings,laboratory visits,and individual communications.We found this input aligned with three overarching science themes.Within each theme we identified two focus areas,or science drivers,that represent the most promising avenues of investi

25、gation for the next 10 to 20 years:Decipher the Quantum RealmElucidate the Mysteries of NeutrinosReveal the Secrets of the Higgs BosonExplore New Paradigms in PhysicsSearch for Direct Evidence of New ParticlesPursue Quantum Imprints of New PhenomenaIlluminate the Hidden UniverseDetermine the Nature

26、of Dark MatterUnderstand What Drives Cosmic EvolutionExectuvie Summary ixDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics

27、 Project Prioritization PanelExecutive Summary xExecutive Summary xiwith dark matter sensitivity,including IceCube Gen-2,and small-scale dark matter experiments using innovative technologies.In the area of colliders,the panel endorses an off-shore Higgs factory,located in either Europe or Japan,to a

28、dvance studies of the Higgs boson following the HL-LHC while maintaining a healthy on-shore particle physics program.The US should actively engage in design studies to establish the technical feasibility and cost envelope of Higgs factory designs.We recommend that a targeted collider panel review th

29、e options after feasibility studies converge.At that point,it is recommended that the US commit funds commensurate with its involvement in the LHC and HL-LHC.In addition to these major initiatives,the panel recommends support for a series of current and future mid-scale projects related to cosmic ev

30、olution,neutrinos,dark matter,and quantum imprints of new phenomena.Small-and mid-scale projects play an essential role,complementing major facili-ties and ensuring the scientific balance of the proposed US program.Notably,small projects can rapidly seize on new opportunities as they arise.In order

31、to preserve this agility,the panel recommends that the Department of Energy(DOE)create a new,competitive program to support a portfolio of small-scale and agile experiments,ASTAE.This program complements the successful Mid-Scale Research Infrastruc-ture(MSRI)and Major Research Instrumentation(MRI)pr

32、ograms at the National Science Foundation(NSF).We recommend continued support for these vital components of the NSF research portfolio.The panel recommends dedicated R&D to explore a suite of promising future projects.One of the most ambitious is a future collider concept:a 10 TeV parton center-of-m

33、o-mentum(pCM)collider to search for direct evidence and quantum imprints of new physics at unprecedented energies.Turning this concept into a cost-effective,realistic collider design demands that we aggressively develop multiple innovative accelerator and detector technologies.This process will esta

34、blish whether a proton,electron,or muon accelerator is the optimal path to our goal.As part of this initiative,we recommend targeted collider R&D to establish the feasibility of a 10 TeV pCM muon collider.A key milestone on this path is to design a muon collider demonstrator facility.If favorably re

35、viewed by the collider panel,such a facility would open the door to building facilities at Fermilab that test muon collider design elements while producing exceptionally bright muon and neutrino beams.By taking up this challenge,the US blazes a trail toward a new future by advancing critical R&D tha

36、t can benefit multiple science drivers and ultimately bring an unparalleled global facility to US soil.Investing in the scientific workforce and enhancing computational and technological infrastructure is crucial.To achieve this goal,funding agencies should support programs that foster a supportive,

37、collaborative work environment;help recruit and retain diverse talent;and reinforce professional standards.Targeted increases in support for theory,general accelerator R&D(GARD),instrumentation,and computing will bolster areas where US leadership has begun to erode.These areas align with na-tional i

38、nitiatives in artificial intelligence and machine learning(AI/ML),quantum The community presented P5 with more inspiring and ambitious projects than either budget scenario could accommodate.To guide the necessary choices,the panel catego-rized projects as small,medium,and large,based on their constr

39、uction cost to the particle physics program.In the large and medium categories,initiatives were first prioritized based on individual scientific merit,then design maturity.An expert subcommittee independently reviewed the costs,technical risks,and schedule of large projects.The final prioritization

40、holistically considered the cost of construction,commissioning,operations,and related research support,distributed over a 10-to 20-year period.This report outlines an ambitious program balanced across science drivers.A mix of large-,medium-and small-scale experiments ensures a continuous stream of g

41、round-breaking research with exceptional discovery potential.The time-sequenced plan is sum-marized in Figure 1.We recommend continuing specific projects,strategically advancing some to the construction phase,and delaying others.Where necessary,individual phases or elements of a large-scale project

42、are prioritized separately.A significant consideration in the prioritization process was the execution of proj-ects begun in the past decade.In addition to operating facilities producing excellent science,three major facilities are currently under construction:the High-Luminosity Large Hadron Collid

43、er(HL-LHC),the Deep Underground Neutrino Experiment(DUNE),and the Vera C.Rubin Observatory(Rubin).Each plays a crucial role in a different facet of the particle physics program.Our partnership in the HL-LHC at CERN will begin to unlock the secrets of the Higgs boson.DUNE is the centerpiece of a deca

44、des-long program to reveal the mysteries of elusive neutrinos.This US-hosted international project will exploit a unique underground laboratory(now nearing comple-tion)and neutrino beams produced at Fermi National Accelerator Laboratory(Fermilab).The Rubin Observatory Legacy Survey of Space and Time

45、(LSST)anchors an ongoing program of cosmic surveys.Realizing the full scientific potential of these and other ongoing projects is our highest priority.The panel identified several crucial areas in cosmic evolution,neutrinos,and dark matter,where next-generation facilities with dramatically enhanced

46、capabilities could have revolutionary impact.The Cosmic Microwave Background Stage IV experiment(CMB-S4)will use telescopes sited in Chile and Antarctica to study the oldest light from the beginning of the universe.Achieving its goals requires unique US infrastructure at the South Pole.Early impleme

47、ntation of a planned accelerator upgrade(Main Injector Ramp and Target;ACE-MIRT)at Fermilab advances the timeline of the DUNE program.The re-envisioned second phase of DUNE,which adds a third underground detector module and an upgraded near detector complex,further expands DUNEs power and scope as a

48、 neutrino laboratory.We preserve research and development(R&D)toward an advanced fourth detector that could ultimately expand DUNEs physics program.A comprehensive program that includes a Generation 3(G3)Dark Matter experi-ment will probe the enigmatic nature of dark matter,which makes up a signific

49、ant portion of the universes mass and energy and has been one of the most enduring mysteries in modern physics.The recommended program also invests in multi-messenger observatories DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsExecutive Summary xiiDRAFT

50、 Report of the 2023 Particle Physics Project Prioritization Panel 1Introductioninformation science(QIS),and microelectronics,creating valuable synergies.Such increased support maximizes the return on scientific investments,fosters innovation,and benefits society in domains from medicine to national

51、security.The impact of the more constrained budget scenario is severe.It forces the US to cede leadership in many initiatives to other regions of the world and reduces investments in workforce and future technologies to critical levels.Specifically,the G3 dark matter exploration would be relocated e

52、lsewhere,and elements of DUNE would be descoped or delayed.This limiting of DUNEs physics reach would negatively impact the reputation of the US as an international host,and more limited contributions to an off-shore Higgs factory would tarnish our standing as a partner for future global facilities.

53、Conversely,a modest increase in budget over the less constrained scenario allows for additional pathways to discovery by accelerating science,leveraging existing investments,and solidifying US scientific leadership in the international context.We have crafted a well-balanced program that is technica

54、lly and financially feasible for the coming 10 years and that builds toward a longer-term vision of US leadership and scientific discovery in particle physics.As this program is realized,we look forward to sharing new insights into the quantum universe.1DRAFT Exploring the Quantum Universe:Pathways

55、to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel1:Introduction 21:Introduction 3The US particle physics program would not exist without the sustained support of the Department of Energy(DOE)and the National Science Foundation(NSF).

56、These agencies have nurtured a world-class scientific enterprise.From the discovery of the Higgs boson and the revelation of the neutrino masses to the stunning realization that the expansion of the universe is now accelerating,this effort has revolutionized our understanding of how the universe wor

57、ks.With each new insight into the universe,scientific exploration encounters escalating challenges.The tools and technologies required to meet those challenges become increasingly sophisticated.Particle physics now operates on a global scale.In isolation,no nation has the finan-cial resources,workfo

58、rce,or technical capacity required to tackle all the most pressing questions of our field.Yet that same scientific program is within the grasp of a collaborative global effort.The US is a major player on that stage,currently hosting an international program in the study of neutrinos and charged lept

59、ons and in dark matter physics and cosmology.We are a major partner in off-shore high-energy collider facilities in Europe and Japan.Each of these initiatives represents a cornerstone in our collective effort to push the boundaries of understanding in particle physics.Since the 2014 Particle Physics

60、 Project Prioritization Panel(P5)report,the US has made significant investments in expanding its capabilities for groundbreaking discoveries in accelerators and deep underground laboratories.The High-Luminosity Large Hadron Collider(HL-LHC)upgrade is proceeding successfully with critical US contribu

61、tions.This project addresses key questions about the Higgs boson while searching for new parti-cles and phenomena.Concurrently,the construction of the Deep Underground Neutrino Experiment(DUNE)and the Long Baseline Neutrino Facility(LBNF)is establishing a world-leading experiment for precision neutr

62、ino studies.This international mega-project on US soil positions the US as a potential host for future projects.The commissioning of the worlds largest digital camera for the Legacy Survey of Space and Time(LSST),is underway,set to be deployed at the nearly completed Vera C.Rubin Observatory.These p

63、rojects hold immense potential for producing groundbreaking scientific discoveries in the coming decade.Mid-scale projects recommended for construction in the previous report,such as the Generation 2 dark matter searches,are either nearing completion or producing exciting new results.Highlights from

64、 the mid-scale program include an early data release from the Dark Energy Spectroscopic Instrument(DESI)and the short baseline neutrino(SBN)experiments setting stringent limits on the existence of sterile neutrinos.The Muon g-2 experiment measuring the anomalous magnetic moment of the muon has obser

65、ved a discrepancy between the measured value and the value predicted by the Standard Model of particle physics,a result that spurs further theoretical developments.The 2023 P5 has been charged with evaluating the international landscape for par-ticle physics and recommending a strategic plan for the

66、 next decade,within the context of a 20-year global vision.We envision a new era of scientific leadership,centered on decoding the quantum realm,unveiling the hidden universe,and exploring novel paradigms.Balancing current and future large-and mid-scale projects with the agility of small projects is

67、 crucial to our vision.We emphasize the importance of investing in a highly skilled scientific workforce 1.1Overview and VisionCuriosity-driven research is at the core of particle physics,a field of science in which we study the building blocks of the subatomic world.In examining these point-like pa

68、r-ticles and their interactions,we decipher the quantum realm.We also look out into the universe,beyond the visible stars,by building instruments that can illuminate the hidden universe.By studying the very small and the very large,realms that are beyond the limits of human perception,we expand our

69、understanding of the world around us and begin to grasp our place in the cosmos.Going beyond phenomena that we can probe using current experiments,we can use theoretical principles to test our current physics understanding and predict new particles and new phenomena;in this way we explore new paradi

70、gms in physics.Within each of these broad themes,we identify compelling questions that define our priorities and drive what instruments we build and what experiments we design.These science drivers change over time,as new discoveries are made and our under-standing deepens.Informed by the community-

71、driven Snowmass planning process,we have identified a new set of three science themes and six science drivers.The drivers evolved from those of the previous decade.Decipher the Quantum RealmElucidate the Mysteries of NeutrinosReveal the Secrets of the Higgs BosonExplore New Paradigms in PhysicsSearc

72、h for Direct Evidence of New ParticlesPursue Quantum Imprints of New PhenomenaIlluminate the Hidden UniverseDetermine the Nature of Dark MatterUnderstand What Drives Cosmic EvolutionDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023

73、Particle Physics Project Prioritization Panel1:Introduction 51:Introduction 4detectors from a few miles(short-baseline)to more than a thousand miles(long-baseline)away to observe how their nature oscillates as they travel.Experiments in SBN oscillation are more compact in scope,allowing us to pursue

74、 specific questions and test new technologies.The SBN effort as recommended by the 2014 P5 is well underway.The design of long-baseline experiments,with detectors placed close to and far from the beam,allows them to act as many experiments in one.For ex-ample,the large volume of a far detector allow

75、s it to detect neutrinos from supernovae and the sun in parallel with long-baseline measurements.We stand on the verge of precision neutrino physics.Recent results from the NOvA and T2K neutrino experiments have confirmed the benchmarks future neutrino experiments must meet.Following the recommendat

76、ions of the previous P5,the DUNE experiment is under construction,with LBNF leveraging the Fermi National Accelerator Laboratory(Fermilab)proton complex to deliver an intense neutrino beam to the nearly complete Sanford Underground Research Facility(SURF)in South Dakota.DUNE will use mas-sive,cryoge

77、nic liquid-argon(LAr)time-projection chambers(LArTPCs)and the intense beam to comprehensively determine the structure of neutrino mixings and the pattern of their masses.The realization and operation of the ProtoDUNE detector prototypes at the CERN Neutrino Platform successfully demonstrated the LAr

78、TPC technology for DUNE.This program is poised to acquire large neutrino interaction datasets to challenge the validity of the neutrino oscillation framework.Both short-and long-baseline programs offer opportunities to search for signatures of unexpected neutrino interactions.They are complemented b

79、y small experiments like COHERENT at the Oak Ridge National Laboratory,which recently announced the discov-ery of a formerly undetected neutrino interaction mode,coherent elastic neutrino-nucleus scattering.A program of neutrino experiments at different scales can ensure that we have the tools and u

80、nderstanding of neutrino interactions and production to enable the potential for discovery of the large facilities being constructed.If a departure from the current neutrino oscillation framework were to be found,there would be interest in muon storage rings as a neutrino source offering precise and

81、 well-characterized neutrino beams.A so-called neutrino factory,whose technology requires research and development(R&D),could propel the neutrino program to new heights of precision oscillation studies.Reveal the Secrets of the Higgs BosonThe Higgs boson,a unique elementary particle devoid of spin,c

82、an interact with all known matter particles.This particle was discovered at the Large Hadron Collider(LHC)with crucial contributions from the US community,just prior to the last P5 report.The existence of the Higgs raises questions about why it is“frozen”in the universe,imbued in a field that gives

83、mass to all elementary particles.To understand the pervasive influence of the Higgs boson,the interactions of the Higgs field with itself,which determine its potential energy,must be thoroughly studied.To date,measurements of the Higgs at the LHC agree with the predictions of the Standard Model.The

84、ATLAS(A Toroidal LHC Apparatus)and CMS(Compact Muon Solenoid)experiments have achieved precise measurements of and enhancing computational and technological infrastructure.Acknowledging the global nature of particle physics,we recognize the importance of international cooperation and sustainability

85、in project planning.We seek to open pathways to innovation and discovery that offer new insights into the mysteries of the quantum universe.1.2 The Particle Physics Landscape Particle physics has been increasingly successful in describing matter,its interactions,and the 14-billion-year evolution of

86、the universe.Our understanding is captured by the Standard Model and the CDM model,a minimal paradigm of cosmology.The development of these paradigms based on detailed experimental investigations and deep theoretical principles is a triumph and hallmark for the field.We strive to answer the question

87、s these paradigms cannot yet address.Here we discuss which existing projects remain central to answering key questions in the current scientific landscape as embodied in the 2023 science drivers.We highlight where exper-imental results demand new initiatives and how theoretical developments of the d

88、ecade influence our path forward.Finally,we note key investments in accelerator technology,detector instrumentation,computing,and theory crucial to the long-term future of the field.1.2.1 Decipher the Quantum RealmThe Standard Model is a remarkable achievement.It provides a comprehensive description

89、 of all known fundamental particles and their interactions.In that framework,the Higgs boson is the key to understanding the origin of particle mass,because particles inter-acting with the Higgs field acquire mass through the Higgs mechanism.However,not all particles behave that way.Neutrinos,the ti

90、niest and most elusive matter particles,once assumed to be massless,appear to defy the predictions of the Standard Model.Their ability to oscillate between flavors is linked to their mass.Yet the connection between the Higgs mechanism and neutrino masses remains a mystery.Elucidating the mysteries o

91、f neutrinos and revealing the secrets of the Higgs boson are essential for understanding the complete picture of particle physics.Each of these science drivers,with its potential to challenge the Standard Model,can act as a key to unlock the quantum realm.Elucidate the Mysteries of NeutrinosNeutrino

92、 interactions are rare,and their behavior is unique.With technology available today we can detect neutrinos from various sources and produce them in large numbers by accelerating intense proton beams on a target.We can aim the produced neutrinos at DRAFT Exploring the Quantum Universe:Pathways to In

93、novation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel1:Introduction 71:Introduction 6Until now,the study of dark matter has focused on a class of theoretically well-mo-tivated candidates called weakly interacting massive particles(WIMPs).Gen

94、eration-2 WIMP dark matter direct-detection experiments recommended in 2014 are in progress.Several are already refining our understanding of dark matter.The next generation of direct WIMP searches will need to be so sensitive that even the elusive neutrinos will be background noise.Reaching this so

95、-called neutrino fog is a clear milestone,at which we cover a large fraction of WIMP theories.Navigating through the neutrino fog will require innovative thinking and R&D of novel technologies.Testing the full range of WIMP theories could require a collider with at least 10 TeV pCM.These endeavors c

96、omplement efforts to study non-WIMP dark matter candidates such as the quantum chromodynamics(QCD)axion and hidden sector particles.Since the 2014 P5 report,both theoretical and experimental efforts to study these theoretically well-motivated candidates have matured.These candidates can be searched

97、for even with small-scale experiments.A class of heavy WIMP dark matter candidates would produce astrophysical signals that reflect their nature.Searches for these signals are part of a broader multi-messenger astrophysics program that maps our universe with light,neutrinos,and gravitational waves.G

98、amma-ray observatories and the neutrino observatory IceCube have begun to place interesting constraints on these candidates,with substantial advances promised by the far more sensitive next-generation observatories.Understand What Drives Cosmic EvolutionLight from the early universe,known as the cos

99、mic microwave background(CMB),carries the imprint of quantum fluctuations left behind by cosmic inflation.Precision measure-ments of the polarization of the CMB have already shaped our understanding of inflation and constrained certain neutrino properties.Future surveys,built on well-established tec

100、hniques,aim to study the imprint of gravitational waves from the inflation era on the CMB.These observations will also constrain new light particle species that may have influenced the universes evolution at an early stage.Galaxy surveys using both imaging and spectroscopy have generated major advan

101、ces in robust,precise constraints on the accelerated expansion rate of the universe.Current data reveal challenges explaining both early-and late-universe observations within the CDM model.More and higher precision data are needed to understand the implications.The complementary spectroscopic and im

102、aging surveys DESI and LSST will take that next step in exploring the limits of the current cosmological paradigm and determining whether it needs to be modified.DESI is already yielding results,while the LSST is expected to begin in 2025.These experiments will be at their most powerful when combine

103、d with each other and with current and future CMB measurements.Early results from both DESI and LSST will shape future priorities.Together with a potential DESI upgrade,they will inform the design of a next-generation spectroscopic survey by telling us which potential science goalsinflation,late-tim

104、e cosmic acceleration,light relics,neutrino masses,and dark mattershould be emphasized.LSST science the Higgs boson mass,confirmed its spin as zero,and measured its lifetime.However,many questions remain about its nature.Machines like the LHC collide high-energy beams of protons to investigate their

105、 fun-damental structure and produce particles of higher mass.The HL-LHC upgrade,starting in 2029,will continue to push the boundaries of our understanding of the Higgs boson by increasing the rate of particle collisions to obtain on the order of 400 million Higgs bosons.It is possible that the Higgs

106、 could decay to entirely novel particle families connected to physics beyond the Standard Model.Upgraded detectors and advances in software and computing,including artificial intelligence/machine learning(AI/ML),will enable the ex-periments to detect rare events with higher efficiency and greater pu

107、rity.These studies will eventually be limited by the challenges of using proton beams,which are composite objects made of quarks and gluons.The next step is to use electron and positron beams to construct a Higgs factory,which would allow precision measurements of the Higgs boson properties and sear

108、ches for exotic decays,possibly into dark matter.Precision studies of the Higgs self-interaction and searches for possible new spin-less particles related to the Higgs require much larger energies per fundamental particle(parton)interaction than previously considered:on the order of 10 TeV or more.F

109、or lepton colliders,this is the nominal collision energy in the center-of-momentum(CM)frame.For proton colliders,the parton-parton interaction energy is roughly a tenth of the CM energy.We refer henceforth to a 10 TeV parton-center-of-momentum(pCM)collider,since this term applies equally to collider

110、s of all types.Realizing such a collider has impacts beyond the Higgs science driver.1.2.2 Illuminate the Hidden UniverseWhen we look backward in cosmic time,we see a universe very different from the one we know today.The universe has evolved from early moments of rapid expansion(cos-mic inflation),

111、which left behind the seeds of its future structure,to intermediate periods dominated by radiation(potentially including unknown light particle species)and dark matter,to our current epoch of accelerated expansion,driven by an unknown component we call dark energy.The CDM paradigm captures the physi

112、cs that governs this evolution,which is out-side the Standard Model.The two science drivers discussed in this section investigate,and potentially challenge,different aspects of this paradigm.Determine the Nature of Dark MatterOur observations of the universe tell us that dark matter exists,but we ha

113、ve yet to de-termine its nature.Cosmic surveys,including LSST and DESI,probe the distribution of dark matter on a variety of length scales and yield essential data about its properties.The remaining efforts,which use a blend of underground facilities,telescopes,quantum sen-sors,and accelerator-based

114、 probes,focus on detecting particle dark matter candidates.DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel1:Introduction 91:Introduction 8The successful completion of the Muon g-2 expe

115、riment has left us with a tantalizing hint of new physics.New techniques it developed for producing and transporting muons are applicable to other current and future experiments.Another initiative,Mu2e,searches for a muon changing to an electron without producing any neutrinos.Detection of this char

116、ged lepton flavor violation effect would be a revolutionary indication of new physics.Mu2e is nearing completion and poised to begin its first run in 2026,with data-taking con-tinuing intermittently until the end of the decade.Future experiments of this type depend on upgrades to Fermilabs accelerat

117、or complex.R&D would be required to establish the feasibility of these upgrades.In addition to studying the nature of the Higgs boson,a Higgs factory would be a highly sensitive probe of quantum imprints of new phenomena.Precision measurements of Higgs couplings could yield information about extende

118、d Higgs sectors.In addition,the large samples of W and Z bosons produced at a Higgs factory would support exceptionally precise studies of electroweak interactions,studies that that indirectly probe an energy scale well beyond the HL-LHC.1.2.4 Interconnected Opportunities The themes and drivers prov

119、ide a useful organizing principle,and they are deeply inter-connected.For example,studies of cosmic evolution provide critical information not only about dark energy and inflation,but also about light relic particles in the early universe,dark matter,and the scale of the neutrino masses.Complementar

120、y measurements ob-tained across science drivers provide a powerful tool for testing paradigms.It is perhaps not surprising that a common thread across many drivers is the need for more powerful accelerators.Future studies of neutrinos and charged lepton flavor violation would likely need higher-inte

121、nsity neutrino,muon,and proton beams.Revealing the secrets of the Higgs boson,characterizing WIMP dark matter,and searching for direct evidence of new particles ultimately requires access to the electroweak scale provided by a collider with pCM energy of 10 TeV.We do not yet have a technology capabl

122、e of building a 10 TeV pCM energy machine,but the case for one is clear.Extensive R&D is required to develop cost-effective options.Possibilities include proton beams with high-field magnets,muon beams that require rapid capture and acceleration of muons within their short lifetime,and conceivably e

123、lectron and positron beams with wakefield acceleration.All three approaches have the potential to revolutionize the field.A demonstrator facility along the path to a 10 TeV pCM muon collider could fit into the evolution of the accelerator complex at Fermilab.Such a demonstrator might produce intense

124、 muon and neutrino beams in addition to performing critical R&D;it could leverage expertise in muon and neutrino beam facilities developed over the past decade.The im-proved accelerator complex could also support beam-dump and fixed-target experiments for direct searches and quantum imprints of new

125、physics.This R&D path therefore aligns with five of the six science drivers.results will drive future survey concepts for the Rubin Observatory.A new technique based on line intensity mapping(LIM)could provide a more complete view of the intermediate period between the period of inflation and our cu

126、rrent era of accelerated cosmic expan-sion.Further study is needed to establish its feasibility.1.2.3 Explore New Paradigms in PhysicsTo gain a deeper understanding of the quantum universe,we must map out unexplored territory beyond the Standard Model and CDM and understand how these two paradigms f

127、it together.Particle accelerators allow us to search for new particles directly and to seek quantum imprints of new phenomena currently beyond our direct reach.This theme is the evolution of the“Explore the Unknown”science driver from 2014.Search for Direct Evidence of New ParticlesDirect searches f

128、or new heavy particles using high-energy accelerators have historically been a strong driver of progress in particle physics.A decade of direct searches for new particles at the LHC has produced a treasure trove of data and a wealth of innovative anal-yses that leverage AI/ML techniques.The discover

129、y of the Higgs boson at the electroweak scale was a triumph,but its small mass remains a mystery.Theoretical and experimental studies indicate that a comprehensive study of the electroweak scale requires colliders with energy of at least 10 TeV pCM,larger than previously assumed.There is new interes

130、t in searching for relatively light but weakly coupled new par-ticles,such as dark matter particles from hidden sector models.Weak coupling implies their production is rare.In this search,our strategy is not to push for the highest possible energy,but for higher-intensity accelerators.Large datasets

131、 from an off-shore Higgs factory will enable direct searches for feebly coupled light states.In the case of hidden sector dark matter,accelerator-based searches using existing beam dumps are sensitive to benchmark models in the MeVGeV mass ranges.Intensity upgrades at the proton beamline at Fermilab

132、 and focused theory efforts may uncover exciting new lines of inquiry.Pursue Quantum Imprints of New PhenomenaNew phenomena at high energies may be probed through their low-energy quantum im-prints.Quantum imprints can manifest in a diverse range of systems,from the relatively light muons and bottom

133、,charm,and strange quarks,to the heaviest known fundamental particles,the top quark and the Higgs boson.The pursuit of these subtle effects requires large data samples.This in turn requires accelerators producing high-intensity beams and precision detectors that can handle the intensity.The LHCb and

134、 Belle II experiments use,respectively,a proton accelerator in Europe and an electron accelerator in Japan for their precision studies of bottom quark systems.Modest upgrades to these experiments will expand their already unprecedented datasets.DRAFT Exploring the Quantum Universe:Pathways to Innova

135、tion and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel1:Introduction 111:Introduction 101.4 Impact on SocietyPushing the frontiers of human knowledge in particle physics requires global scientific col-laborations,state-of-the-art research facilit

136、ies,and infrastructure to support the ambitious projects that advance science.In collaborating on and coordinating large international efforts,scientists connect irrespective of their backgrounds,making particle physics an enterprise that transcends borders,boundaries,cultures,and societies.Discover

137、ies of new laws of nature that deepen our understanding of the inner work-ings of the universe not only excite scientists but continue to amaze the public and inspire many people to pursue careers in science,technology,engineering,and mathematicsthe STEM fields.Nurturing and developing the next gene

138、ration of scientists and training a highly-skilled workforce are two of the benefits to society.Particle physics has a long-proven record of creating new technologies that have revolutionized our daily experience,such as the world wide web and life-saving medical applicationsfrom cancer treatment to

139、 medical imagingderived from particle acceler-ator and detector technologies.The tools developed for particle physics research also impact society through their adoption by other scientific fields.Applications in chemistry and materials science,for instance,have led to innovations in drug discovery

140、and the design and realization of novel materials.Particle physics provides a training ground for a skilled workforce that drives not only fundamental science,but quantum information science,AI/ML,computational mod-eling,finance,national security,and microelectronics.The US has led the way in many g

141、roundbreaking discoveries in particle physics and is poised to continue its leadership role with sustained investment.1.5 Process and Criteria The 2023 P5 is charged with developing a fiscally viable 10-year strategic plan for US particle physics.The charge further specified that this 10-year plan s

142、hould fit in the con-text of a 20-year vision(see Appendix 1).The recommended program must reflect the scientific interests of the particle phys-ics community.The 2021 Snowmass Community Planning Exercise,organized by the Division of Particles and Fields of the American Physical Society,provided ini

143、tial input to the deliberations of the P5 panel.To fully capture the views of the community,the panel solicited additional input through town hall meetings,laboratory visits,and individual 1.3 Enabling Capabilities and National Initiatives The US has world-renowned capabilities in particle physics.T

144、he national laboratories operate some of the most powerful and sophisticated particle accelerators and detectors in the world and attract some of the brightest minds in science and engineering.Fermilab,the only single-purpose laboratory for particle physics in the US,and Argonne(ANL),Brookhaven(BNL)

145、,Lawrence Berkeley(LBNL)and SLAC National Laboratories,with their complementary strengths,provide unique infrastructure and technical capabilities for innovation and discovery in particle physics.US universities play an important role in experimental and theoretical research and in educating the nex

146、t generation of scientists.US national initiatives in quantum science,microelectronics,and AI/ML as well as general accelerator and detector R&D have an outsized impact on the field.They lead to new approaches in experiment and theory,and they inspire new experiments and detector upgrades.The US pro

147、gram leads in the application of AI/ML to particle physics,and recent advances in computing are beginning to revolutionize detector development,data taking,analysis,simulation,and accelerator design.The field continues to make substantial contributions to the initiatives on quantum information scien

148、ce and micro-electronics.The US is also leading theoretical developments in particle physics,which has been crucial in providing guidance to experiments,interpreting data,and uncovering fundamental theories.New particle detectors with enhanced sensitivity and accelerators that provide beams at highe

149、r energies and intensities have been key to the advancement of the field.Particle physics is the steward of accelerator R&D,together with our partners in nuclear physics,basic energy sciences(BES),accelerator R&D and production,and applied science.In addition,the development of infrastructure suppor

150、ting scientific research at the South Pole and the creation of a deep underground laboratory in the US have opened new facilities for discovery science.The South Pole station and surrounding science lab-oratories are a one-of-a-kind research facility maintained by the US.The unique location provides

151、 an unparalleled view of the universe and allows for science that is not accessi-ble elsewhere.The infrastructure and support of the South Pole station and its science program are critical for the study of the CMB and astrophysical neutrinos.The construction of SURF in the US enables the precision s

152、tudies of neutrinos and the search for dark matter in an environment shielded by Earth.With SURF,the US has created a premier underground laboratory that is built on a decades-old distinguished history.The realization of this facility adds unparalleled infrastructure capability to the suite of natio

153、nal laboratories in the US.This facility enables the US to be an international host for neutrino and dark matter experiments recommended in this report.DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prior

154、itization Panel1:Introduction 131:Introduction 12The panel also considered broader questions of how this program should be carried out.We discuss ethical conduct in the field and present recommendations to build a more inclusive and respectful community that draws on all talent in the nation and bey

155、ond.1.6Roadmap to the ReportSection 1 introduces the science drivers and our vision for particle physics as well as the process and criteria for the P5 deliberations.The recommendations are presented in section 2.Brief discussions expand on the infrastructure and expertise required to carry them out

156、 as well as the importance of international and inter-agency partnerships.The subsequent sections discuss how the program can be adapted to alternative budget scenarios,both for less favorable and for more favorable funding.Sections 3,4,and 5 describe the impact of these recommenda-tions on the thre

157、e science themes.Additional area recommendations are made in section 6,which highlight theoret-ical,computational,and technological areas where sustained investments can advance the future of science and technology.In those recommendations,the panel explicitly indi-cates the increase in annual fundi

158、ng needed to achieve the fields 20-year goalsthese increases should be achieved through a ramp,lasting no more than five years,between current and new funding levels.Section 7 expands on the recommendation supporting a technologically advanced workforce.Additional budgetary considerations are descri

159、bed in section munications.The panel was especially encouraged by the active participation of early career members in the community-driven planning process.They represent the future of our field and are essential to the realization of the goals and aspirations detailed in this report.During the pane

160、ls deliberations,there was consensus that the overall program should enable US leadership in core areas of particle physics.It should leverage unique US facilities and capabilities,engage with core national initiatives to develop key tech-nologies,and develop a skilled workforce for the future that

161、draws on US talent.Effective engagement and leadership in international endeavors were also considerations.The community presented P5 with more inspiring and ambitious projects than fiscal reality could accommodate.In selecting projects,the panel considered a projects indi-vidual scientific merit an

162、d potential for transformational discovery as well as how well the project met criteria for the overall program.The DOE provided the panel with two budget scenarios for High Energy Physics(HEP)derived from realistic near-term budget projections.The baseline scenario assumes budget levels for HEP for

163、 fiscal years 2023 through 2027 that are specified in the Creating Helpful Incentives to Produce Semiconductors(CHIPS)and Science Act of 2022.The baseline budget scenario then increases by 3%per year from fiscal year 2028 through 2033.The less favorable scenario assumes increases of 2%per year from

164、fiscal year 2024 to 2033.The panel was asked to develop DOE programs consistent with these scenarios.Prioritization of projects that would receive funding from the DOE therefore had to con-sider both project cost and the uncertainties in that cost related to the projects technical readiness and desi

165、gn maturity.For projects where the US contribution is expected to come entirely from the NSF,the panel was only asked to consider scientific relevance to the US particle physics program.We note that in a number of cases,the NSF science case for a jointly funded project extends beyond particle physic

166、s into astrophysics.The panel categorized projects as small($250M)based on the US contribution to their construction cost.In the large and me-dium categories,initiatives were first prioritized based on individual scientific merit,then assessed on project maturity and technical risk.The balance of pr

167、oject timescales was also considered,in order to ensure delivery of scientific results throughout the decade and opportunities for scientists at all career levels.The final prioritization holistically consid-ered the cost of construction,commissioning,operations,and related research support,distribu

168、ted over a 10-to 20-year period.The panel generally did not consider individual projects,as per the charge,but did note areas where small projects could be particularly effective.As part of this process,the panel established budget profiles in FY23 dollars with assumptions on inflation as described

169、in section 8.To help the P5 panel better understand costs,schedules,and risks of the large projects,a subcommittee was convened with project management and technical experts from the community.The subcommittee provided an independent assessment of the cost range,schedule,and risks of the major proje

170、cts.That input was used to assess the most likely cost scenarios and reduce the chance of unexpected budget overruns from current and new projects into the next decade.DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physi

171、cs Project Prioritization Panel 15 2The Recommended Particle Physics Program“By studying the very small and the very large,realms that are beyond the limits of human perception,we expand our understanding of the world around us and begin to grasp our place in the cosmos.”DRAFT Exploring the Quantum

172、Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Particle Physics Program 172:The Recommended Particle Physics Program 16There is a compelling physics case for constructing a 10 TeV or more pCM co

173、llider.Such a collider would search for direct evidence and quantum imprints of new particles and forces at unprecedented energies.There are several approaches:a 10 TeV muon collider,a 100 TeV proton-proton collider such as FCC-hh at CERN,or possibly a 10 TeV high-energy e+e or-collider based on the

174、 wakefield acceleration technology.Any of them would enable a comprehensive physics portfolio that includes ultimate measurements in the Higgs sector,a broad search program providing access to new hidden sectors by producing a substantially higher mediator mass or probing even smaller coupling,and o

175、pportunities to produce new particles directly.All options for a 10 TeV pCM collider are new technologies under development and R&D is required before we can embark on building a new collider.Further insights will be gained over this decade through collaboration and planning with international partn

176、ers and dedicated R&D efforts aimed at addressing technical chal-lenges.A panel in the latter part of the decade will be able to harness this information to make further decisions on the path toward future colliders.A transformative next-generation CMB experiment,CMB-S4,will plumb the secrets of the

177、 primordial universe during and immediately after a period of rapid expansion;it should reveal signatures of new physics at energies far beyond the reach of colliders.The ongoing galaxy survey program,enhanced by the Dark Energy Spectroscopic Instrument initiative DESI-II,investigates the cause for

178、a more recent era of accelerated expansion.Together,they promise revolutionary insight into the drivers of cosmic evolution.In parallel,a strong R&D effort builds toward the ultimate next-generation wide-field spectroscopic survey Spec-S5,which will study the possible time evolution of dark energy a

179、nd provide a test of inflation complementary to CMB-S4.Development of the emerging technology of line-intensity mapping could create a 3D map of the universe and enable theoretically clean and powerful tests of cosmology.Another suite of experiments pursues the undetermined nature of the dark matter

180、 that gravitationally influences our universe.Select dark matter experiments searching for WIMPs will reach critical discovery potential for a broad range of WIMP masses.Small-er-scale experiments will survey the wider set of dark matter theories and their parameter space.In total,these efforts prom

181、ise an unprecedented view of the hidden universe.A new DOE portfolio of agile projects across all science drivers complements existing opportunities within NSF.This portfolio plays a pivotal role in achieving a balanced and forward-looking program.Realizing the full potential of the experimental lan

182、dscape requires not just targeted R&D,but substantial strategic investments in theory and infrastructure.Just as hints of new physics revealed by experiment drive new theoretical developments,theory guides experimental inquiries and enriches our understanding of fundamental principles.A coordinated

183、effort that develops shared cyberinfrastructure,harnesses emerging tech-nologies,and leverages national initiatives such as AI,microelectronics,and quantum information science(QIS)benefits all aspects of our scientific program.Equally crucial,key facilities must be maintained and developed in alignm

184、ent with the long-term vision outlined in this report.2.1Overview A particle physics program that tackles the most important questions in each of the science drivers maximizes its potential for groundbreaking scientific discovery.Executing such a program requires a balanced portfolio of large,medium

185、,and small projects,coupled with substantial investments in forward-looking R&D and the development of a skilled workforce for the nation.Building upon the foundations laid by the previous P5,our recommended program completes ongoing projects and capitalizes on their momentum.A suite of new initiati

186、ves at a range of scales includes major projects that will shape the scientific landscape over the next two decades.The prioritized time sequencing of recommended projects and R&D,summarized in Figure 1,reflects our current understanding of the scientific landscape and its associated uncertainties.T

187、he overall program is carefully constructed to be compatible with the baseline budget scenario provided by DOE.To achieve that,we recommend continuing specific projects,strategically advancing some to the construction phase,and delaying others.As shown in Figure 1,in some cases individual phases or

188、elements of large-scale projects had to be prioritized separately.The process and criteria by which the recommended initiatives were selected are laid out in section 1.5.We note our commitment to the ongoing projects described in section 1.The scientific direction and balance of the recommended new

189、initiatives are summarized below.DUNE will comprehensively explore the quantum realm of neutrinos,potentially unearthing new physics beyond current theoretical frameworks.Early implementation of the accelerator upgrade ACE-MIRT advances the DUNE program significantly,hastening the definite discovery

190、 of the neutrino mass ordering.This upgrade in conjunction with the deployment of the third far detector and a more capable near detector are indispensable components of the re-envisioned next phase of DUNE.R&D for an advanced fourth de-tector enables the expansion of the physics program of LBNF.The

191、se substantial initiatives find synergy with smaller-scale experiments to elucidate the mysteries of neutrinos.A Higgs factory is the next step toward fully revealing the secrets of the Higgs bo-son within the quantum realm.We advocate substantial US participation in the design and construction of a

192、ccelerators and detectors for an off-shore facility,and we advocate investment of effort to support development of the Future Circular Collider-electron(e)positron(e+)(FCC-ee)and the International linear Collider(ILC),along with a parallel and increasingly intensive program of R&D pursuing revolutio

193、nary accelerator and detector technologies.These are crucial for a leadership role in the design and construction of the Higgs factory and for our aspiration to lead and potentially host a next high-energy collider facility beyond the Higgs factory.DRAFT Exploring the Quantum Universe:Pathways to In

194、novation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Particle Physics Program 192:The Recommended Particle Physics Program 18c.The Vera C.Rubin Observatory to carry out the LSST,and the LSST Dark Energy Science Collaboratio

195、n,to understand what drives cosmic evolution(section 4.2).In addition,we recommend continued support for the following ongoing experiments at the medium scale(project costs$50M for DOE and$4M for NSF),including completion of construction,operations,and research:d.NOvA,SBN,and T2K(elucidate the myste

196、ries of neutrinos,section 3.1).e.DarkSide-20k,LZ,SuperCDMS,and XENONnT(determine the nature of dark matter,section 4.1).f.DESI(understand what drives cosmic evolution,section 4.2).g.Belle II,LHCb,and Mu2e(pursue quantum imprints of new phenomena,section 5.2).The agencies should work closely with eac

197、h major project to carefully manage the costs and schedule to ensure that the US program has a broad and balanced portfolio.Recommendation 2:Construct a portfolio of major projects that collectively study nearly all fundamental constituents of our universe and their interactions,as well as how those

198、 interactions determine both the cosmic past and future.These projects have the potential to transcend and transform our current paradigms.They inspire collaboration and international cooperation in advancing the frontiers of human knowledge.Plan and start the following major initiatives in order of

199、 priority from highest to lowest:a.CMB-S4,which looks back at the earliest moments of the universe to probe physics at the highest energy scales.It is critical to install telescopes at and observe from both the South Pole and Chile sites to achieve the science goals(section 4.2).b.Re-envisioned seco

200、nd phase of DUNE with an early implementation of an enhanced 2.1 MW beamACE-MIRTa third far detector,and an upgraded near-detector complex as the definitive long-baseline neutrino oscillation experiment of its kind(section 3.1).c.An off-shore Higgs factory,realized in collaboration with internationa

201、l partners,in order to reveal the secrets of the Higgs boson.The current designs of FCC-ee and ILC meet our scientific requirements.The US should actively engage in feasibility and design studies.Once a specific project is deemed feasible and well-defined(see also Recommendation 6),the US should aim

202、 for a contribution at funding levels com-mensurate to that of the US involvement in the LHC and HL-LHC,while maintaining a healthy US on-shore program in particle physics(section 3.2).d.An ultimate Generation 3(G3)dark matter direct detection experiment reaching the neutrino fog,in coordination wit

203、h international partners and preferably sited in the US(section 4.1).e.IceCube-Gen2 for study of neutrino properties using non-beam neutrinos complemen-tary to DUNE and for indirect detection of dark matter covering higher mass ranges using neutrinos as a tool(section 4.1).An ambitious,effective sci

204、entific program thrives when pursued by a vibrant scientific community.We therefore endorse strategic initiatives to collectively amplify and strengthen the workforce while fostering a healthy working environment.These initiatives are designed to uphold ethical conduct of research,dismantle barriers

205、 to entry and retention,recruit broadly,and pave new pathways of opportunity.This commitment nurtures an advanced technological workforce not only adept in particle physics but also equipped to contribute to the technological advancements essential for the nation.The vision outlined in this report p

206、rovides opportunities for paradigm-shifting discov-eries.By deciphering the quantum realm,illuminating the hidden universe,and exploring new paradigms in physics,we step further into our quantum universe.Some of the pri-orities are designed to adapt naturally as this landscape evolves over the next

207、decade,while others are designed to drive that evolution.2.2Recommendations To drive US particle physics forward and maintain strong global leadership,we advocate a comprehensive and balanced program that strategically addresses the three science themes and their six interwoven drivers.The numerical

208、 order of the recommendations listed below is not meant to reflect their relative priority;instead it is used to group them thematically.The lists under the recommendations are not prioritized,except for the list of major projects under Recommendation 2.Each recommendation is stated in boldface,foll

209、owed by concise,lettered explanations of how the recommendation can be realized.The impact of alternative budget scenarios on the different elements of the program is discussed in section 2.6.A Full List of Recommendations is provided at the end of the report.That list includes Area Recommendations(

210、section 6)in addition to those here.Recommendation 1:As the highest priority independent of the budget sce-narios,complete construction projects and support operations of ongoing experiments and research to enable maximum science.We reaffirm the previous P5 recommendations on major initiatives:a.HL-

211、LHC(including ATLAS and CMS detectors,as well as Accelerator Upgrade Project)to start addressing why the Higgs boson condensed in the universe(reveal the secrets of the Higgs boson,section 3.2),to search for direct evidence for new particles(section 5.1),to pursue quantum imprints of new phenomena(s

212、ection 5.2),and to determine the nature of dark matter(section 4.1).b.The first phase of DUNE and PIP-II to determine the mass ordering among neutri-nos,a fundamental property and a crucial input to cosmology and nuclear science(elucidate the mysteries of neutrinos,section 3.1).DRAFT Exploring the Q

213、uantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Particle Physics Program 212:The Recommended Particle Physics Program 20c.Expand the General Accelerator R&D(GARD)program within HEP,includi

214、ng stew-ardship(section 6.4).d.Invest in R&D in instrumentation to develop innovative scientific tools(section 6.3).e.Conduct R&D efforts to define and enable new projects in the next decade,including detectors for an e+e Higgs factory and 10 TeV pCM collider,Spec-S5,DUNE FD4,Mu2e-II,Advanced Muon F

215、acility,and line intensity mapping(sections 3.1,3.2,4.2,5.1,5.2,and 6.3).f.Support key cyberinfrastructure components such as shared software tools and a sustained R&D effort in computing,to fully exploit emerging technologies for proj-ects.Prioritize computing and novel data analysis techniques for

216、 maximizing science across the entire field(section 6.7).g.Develop plans for improving the Fermilab accelerator complex that are consistent with the long-term vision of this report,including neutrinos,flavor,and a 10 TeV pCM collider(section 6.6).We recommend specific budget levels for enhanced supp

217、ort of these efforts and their justifications as Area Recommendations in section 6.Recommendation 5:Invest in initiatives aimed at developing the workforce,broadening engagement,and supporting ethical conduct in the field.This com-mitment nurtures an advanced technological workforce not only for par

218、ticle physics,but for the nation as a whole.The following workforce initiatives are detailed in section 7:a.All projects,workshops,conferences,and collaborations must incorporate ethics agreements that detail expectations for professional conduct and establish mecha-nisms for transparent reporting,r

219、esponse,and training.These mechanisms should be supported by laboratory and funding agency infrastructure.The efficacy and coverage of this infrastructure should be reviewed by a HEPAP subpanel.b.Funding agencies should continue to support programs that broaden engagement in particle physics,includi

220、ng strategic academic partnership programs,traineeship programs,and programs in support of dependent care and accessibility.A systematic review of these programs should be used to identify and remove barriers.c.Comprehensive work-climate studies should be conducted with the support of fund-ing agenc

221、ies.Large collaborations and national laboratories should consistently undertake such studies so that issues can be identified,addressed,and monitored.Professional associations should spearhead field-wide work-climate investigations to ensure that the unique experiences of individuals engaged in sma

222、ller collaborations and university settings are effectively captured.d.Funding agencies should strategically increase support for research scientists,re-search hardware and software engineers,technicians,and other professionals at universities.The prioritization principles behind these recommendatio

223、ns can be found in sections 1.6 and 8.1.IceCube-Gen2 also has a strong science case in multi-messenger astrophysics together with gravitational wave observatories.We recommend that NSF expand its ef-forts in multi-messenger astrophysics,a unique program in the NSF Division of Physics,with US involve

224、ment in the Cherenkov Telescope Array(CTA;recommendation 3c),a next-generation gravitational wave observatory,and IceCube-Gen2.Recommendation 3:Create an improved balance between small-,medium-,and large-scale projects to open new scientific opportunities and maximize their results,enhance workforce

225、 development,promote creativity,and com-pete on the world stage.In order to achieve this balance across all project sizes we recommend the following:a.Implement a new small-project portfolio at DOE,Advancing Science and Technolo-gy through Agile Experiments(ASTAE),across science themes in particle p

226、hysics with a competitive program and recurring funding opportunity announcements.This program should start with the construction of experiments from the Dark Matter New Initiatives(DMNI)by DOE-HEP(section 6.2).b.Continue Mid-Scale Research Infrastructure(MSRI)and Major Research Instru-mentation(MRI

227、)programs as a critical component of the NSF research and project portfolio.c.Support DESI-II for cosmic evolution,LHCb upgrade II and Belle II upgrade for quan-tum imprints,and US contributions to the global CTA Observatory for dark matter(sections 4.2,5.2,and 4.1).The Belle II recommendation inclu

228、des contributions towards the SuperKEKB accelerator.Recommendation 4:Support a comprehensive effort to develop the resourc-estheoretical,computational,and technologicalessential to our 20-year vision for the field.This includes an aggressive R&D program that,while technologically challenging,could y

229、ield revolutionary accelerator designs that chart a realistic path to a 10 TeV pCM collider.Investing in the future of the field to fulfill this vision requires the following:a.Support vigorous R&D toward a cost-effective 10 TeV pCM collider based on proton,muon,or possible wakefield technologies,in

230、cluding an evaluation of options for US siting of such a machine,with a goal of being ready to build major test facilities and demonstrator facilities within the next 10 years(sections 3.2,5.1,6.5,and Recom-mendation 6).b.Enhance research in theory to propel innovation,maximize scientific impact of

231、invest-ments in experiments,and expand our understanding of the universe(section 6.1).DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Particle Physics Program 232:The

232、Recommended Particle Physics Program 2210 TeV pCM muon collider is almost exactly the size of the Fermilab campus.A muon collider would rely on a powerful multi-megawatt proton driver delivering very intense and short beam pulses to a target,resulting in the production of pions,which in turn decay i

233、nto muons.This cloud of muons needs to be captured and cooled before the bulk of the muons have decayed.Once cooled into a beam,fast acceleration is required to further suppress decay losses.Each of these steps presents considerable technical challenges,many of which have never been confronted befor

234、e.This P5 plan outlines an aggressive R&D program to determine the parameters for a muon collider test facility by the end of the decade.This facility would test the feasibility of developing a muon collider in the following decade.With a 10 TeV pCM muon collider at Fermilab as the long-term vision,

235、a clear path for the evolution of the current proton accelerator complex at Fermilab emerges natu-rally:a booster replacement with a suitable accumulator/buncher ring would pave the way to a muon collider demonstration facility(Recommendation 4g,6).The upgraded facility would also generate bright an

236、d well-characterized neutrino beams bringing natural synergies with studies of neutrinos beyond DUNE.It would also support beam dump and fixed target experiments for direct searches of new physics.Another synergy is in charged lepton flavor violation.The current round of searches at Mu2e can reveal

237、quantum imprints of new physics at the 100 TeV energy scale,beyond the reach of di-rect searches at collider facilities in the foreseeable future.An intense muon facility may push this search even further.Although we do not know if a muon collider is ultimately feasible,the road toward it leads from

238、 current Fermilab strengths and capabilities to a series of proton beam improve-ments and neutrino beam facilities,each producing world-class science while performing critical R&D towards a muon collider.At the end of the path is an unparalleled global facility on US soil.This is our Muon Shot.2.4St

239、ewardship of Key Infrastructure and ExpertiseSuccessful completion of the recommended major projects depends on critical US infra-structure(section 6.6),including particular research sites and facilities.DOE National Laboratories are critical research infrastructure that must be maintained and enhan

240、ced based on the needs of the particle physics community.This is particularly true for Fer-milab as the only dedicated US laboratory for particle physics.The South Pole,a unique site that enables the world-leading science of CMB-S4 and IceCube-Gen2,must be maintained as a premier site of science to

241、allow continued US leadership in these areas.SURF,a deep underground research laboratory supported by the South Dakota Science e.A plan for dissemination of scientific results to the public should be included in the proposed operations and research budgets of experiments.The funding agencies should

242、include funding for the dissemination of results to the public in operation and research budgets.Recommendation 6:Convene a targeted panel with broad membership across particle physics later this decade that makes decisions on the US accelera-tor-based program at the time when major decisions concer

243、ning an off-shore Higgs factory are expected,and/or significant adjustments within the accel-erator-based R&D portfolio are likely to be needed.A plan for the Fermilab accelerator complex consistent with the long-term vision in this report should also be reviewed.The panel would consider the followi

244、ng:a.The level and nature of US contribution in a specific Higgs factory including an evalu-ation of the associated schedule,budget,and risks once crucial information becomes available.b.Mid-and large-scale test and demonstrator facilities in the accelerator and collider R&D portfolios.c.A plan for

245、the evolution of the Fermilab accelerator complex consistent with the long-term vision in this report,which may commence construction in the event of a more favorable budget situation.2.3The Path to 10 TeV pCMRealization of a future collider will require resources at a global scale and will be built

246、 through a world-wide collaborative effort where decisions will be taken collectively from the outset by the partners.This differs from current and past international projects in particle physics,where individual laboratories started projects that were later joined by other laboratories.The proposed

247、 program aligns with the long-term ambition of hosting a major international collider facility in the US,leading the global effort to understand the fundamental nature of the universe.There are multiple complementary technologies that could potentially reach the 10 TeV pCM scale,and the work to dete

248、rmine how to economically reach that goal must go forward.This is why we recommend pursuing revolutionary R&D in areas such as high-field magnets,a multi-megawatt proton driver,wakefield accelerator technology,and muon cooling(Recommendation 4a).In particular,a muon collider presents an attractive o

249、ption both for technological innovation and for bringing energy frontier colliders back to the US.The footprint of a DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Pa

250、rticle Physics Program 252:The Recommended Particle Physics Program 24We note that there are many synergies between muon and proton colliders,especially in the area of development of high-field magnets.R&D efforts in the next 5-year timescale will define the scope of test facilities for later in the

251、 decade,paving the way for initiating demonstrator facilities within a 10-year timescale(Recommendation 6).For studies of cosmic evolution and astrophysical studies of dark matter,inter-agen-cy coordination and cooperation between DOE,NSF,and NASA using complementary observational approaches has bee

252、n very productive in building a world-leading scientific program.Such coordination and cooperation should continue.The field of particle physics is not an isolated endeavor,and it benefits from and contributes to neighboring areas in nuclear physics,astrophysics and astronomy,con-densed matter physi

253、cs,precision physics,computing,instrumentation,material science,and others.At the same time,it provides important theoretical and technological input to these areas,as well as medical,security,and many other fields,some as seemingly unrelated as archaeology.Funding agencies are urged to reach across

254、 the traditional boundaries to enhance collaboration,maximize science,and develop a strong workforce for the nation overall.2.6Adapting to Alternative Budget ScenariosThe program recommendations are built considering the baseline budget scenario for DOE.This scenario assumes budget levels for HEP fo

255、r fiscal years 2023 through 2027 that are specified in the CHIPS and Science Act of 2022.The baseline budget scenario then increases by 3%per year from fiscal year 2028 through 2033.We assume 3%infla-tion throughout our exercise,so it provides an initial increase over five years followed by an essen

256、tially flat budget in later years.In this scenario,hard choices were required as described in section 8.2.The recommended program is well-balanced and forward-looking,enabling scientific breakthroughs and maintaining scientific and technological leadership.Two other scenarios were considered by the

257、panel.Figure 2 summarizes the projects recommended under all three scenarios.2.6.1 Less Favorable Budget Scenario We are charged to discuss a less favorable budget scenario that forces us to make more drastic and challenging choices.This scenario assumes budget increases of 2%per year during fiscal

258、years 2024 to 2033 for DOE HEP,which is an erosion against an assumed 3%annual inflation rate.Under this scenario,some interesting scientific opportunities are still achievable,but scientific progress is significantly slowed.and Technology Authority,private foundation funds,and DOE,is a critical add

259、ition to the suite of US research infrastructure,providing new space and essential infrastructure for DUNE and potentially a G3 dark matter experiment.In other cases,the infrastructure is technological and intellectual.The GARD program is critical in supporting a broad range of accelerator science a

260、nd technology(AS&T)for DOEs Office of Science,separate from the targeted R&D toward future colliders.Along with NSF-funded fundamental accelerator science,GARD supports a broad workforce of essential accelerator expertise.The program also provides stewardship of AS&T for DOEs Office of Science.This

261、program and the balance across the different research thrusts should be reviewed regularly to ensure alignment with the goals in particle physics.Reviews should be conducted by broad teams,not only specialists.2.5International and Inter-Agency PartnershipsMajor facilities like Fermilab in the US,CER

262、N in Europe,and KEK in Japan have led the worldwide effort to advance accelerator-based studies of particle physics.These facilities have enabled many groundbreaking experiments,and their continued leadership roles as host laboratories for future accelerators,cutting-edge experiments,and hubs for in

263、-ternational collaborations are important for progress in the field.Successful completion of the recommended major projects depends on significant coordination and collaboration among US agencies and international partners.Large international projects such as a Higgs factory and DUNE require not onl

264、y DOE and NSF,but also the US Department of State and other entities in the federal government to work with global partners to establish the complex frameworks involved.In the case of the Higgs factory,crucial decisions must be made in consultation with potential international partners.The FCC-ee fe

265、asibility study is expected to be completed by 2025 and will be followed by a European Strategy Group update and a CERN coun-cil decision on the 2028 timescale.The ILC design is technically ready and awaiting a formulation as a global project.A dedicated panel should review the plan for a specific H

266、iggs factory once it is deemed feasible and well-defined;evaluate the schedule,bud-get and risks of US participation;and give recommendations to the US funding agencies later this decade(Recommendation 6).When a clear choice for a specific Higgs factory emerges,US efforts will focus on that project,

267、and R&D related to other Higgs factory projects would ramp down.Parallel to the R&D for a Higgs factory,the US R&D effort should develop a 10 TeV pCM collider,such as a muon collider,a proton collider,or possibly an electron-positron collider based on wakefield technology.The US should participate i

268、n the International Muon Collider Collaboration(IMCC)and take a leading role in defining a reference design.DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Particle Ph

269、ysics Program 272:The Recommended Particle Physics Program 26ii.Pursue an expanded DOE AS&T initiative to develop foundational technologies for particle physics that can benefit applications across science,medicine,se-curity,and industry.iii.Pursue broad accelerator science and technology developmen

270、t at both DOE and NSF,including partnerships modeled on the plasma science partnership.b.Small Projects Expand the portfolio of agile experiments to pursue new science,enable discov-ery across the portfolio of particle physics,and provide significant training and leadership opportunities for early c

271、areer scientists.c.Medium Projectsi.Initiate construction of Spec-S5 as the world-leading study of cosmic evolution,with applications to neutrinos and dark matter,once its design matures.ii.Initiate construction of an advanced fourth far detector(FD4)for DUNE that will expand its neutrino oscillatio

272、n physics and broaden its science program.iii.Initiate construction of a second G3 dark matter experiment to maximize discov-ery potential when combined with the first one.d.Large Projects Evolve the infrastructure of the Fermilab accelerator complex to support a future 10 TeV pCM collider as a glob

273、al facility.A positive review of the design by a targeted panel may expedite its execution(Recommendation 6).In this scenario,we would aim for a program that covers most areas of particle phys-ics for the next 10 years,maintaining continuity and exploiting the ongoing projects in Recommendation 1 as

274、 our highest priority.The agencies should launch the same major initiatives as outlined in Recommendation 2,some of them with significantly reduced scope:a.CMB-S4 without reduction in scope.b.DUNE Third Far Detector(FD3),but defer ACE-MIRT and the More Capable Near Detector(MCND).c.Contribution to a

275、n off-shore Higgs factory delayed and at a reduced level.d.Reduced participation in an off-shore G3 dark matter experiment and no SURF expansion.e.IceCube-Gen2 without reduction in scope.The rationale for this prioritization is given in section 8.3.Recommendations 3 and 4 are crucial for maintaining

276、 the health and balance of the field.While these recommendations still apply,they receive reduced support in scenarios between the baseline and less favorable conditions.Reductions to all items in these two recommendations should be proportionate.Research must be supported at least at the current le

277、vel.Recommendation 5 is deemed a high priority and is supported in all scenarios.Recommendation 6 applies in all scenarios.This less favorable scenario will lead to a loss of US leadership in many areas,es-pecially the science of the G3 dark matter experiment,and will damage our reputation as a reli

278、able international host for DUNE and as a partner for a Higgs factory.We still make investments in the future,but at a significantly reduced level for small-scale experiments,including ASTAE,theory,computing,instrumentation,and collider R&D.In this scenario,it would be increasingly difficult to main

279、tain US competitiveness as an international partner in accelerator technology.See section 8.3 for more details.2.6.2 More Favorable Budget Scenario In a budget outlook more favorable than the baseline budget scenario,we urge the fund-ing agencies to support additional scientific opportunities.Even a

280、 small increase in the overall budget enables a large return on the investment,serving as a catalyst to acceler-ate scientific discovery and to unlock new pathways of inquiry.The opportunities include R&D,small projects,and the construction of advanced detectors for flagship projects in the US.They

281、are listed below in four categories from small to large in budget size:a.R&Di.Increase investment in detector R&D targeted toward future collider concepts for a Higgs factory and 10 TeV pCM collider in order to accelerate US leadership in this area.DRAFT Exploring the Quantum Universe:Pathways to In

282、novation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel2:The Recommended Particle Physics Program 282:The Recommended Particle Physics Program 29TEST FACILITIESGARD TheoryInstrumentationComputingLHCLZ,XENONnTNOvA/T2KSBNDESI/DESI-IIBelle IISupe

283、rCDMSRubin/LSST&DESCMu2eDarkSide-20kHL-LHCDUNE Phase ICMB-S4CTAG3 Dark Matter IceCube-Gen2DUNE FD3DUNE MCNDHiggs factory DUNE FD4 Spec-S5 Mu2e-IIMulti-TeV LIMApproximate timeline of the recommended program within the baseline scenario.Projects in each cate-gory are in chronological order.For IceCube

284、-Gen2 and CTA,we do not have information on budgetary constraints and hence timelines are only technically limited.The primary/secondary driver designation reflects the panels understanding of a projects focus,not the relative strength of the science cases.Projects that share a driver,whether primar

285、y or secondary,generally address that driver in different and complementary ways.OperationIndex:ConstructionR&D,ResearchP:Primary S:SecondaryPPSSPSSPPPPSSPPPPPPSSPSPPSSPSSSPPPPPPPPSSSPSSSPSPPPPPSSSPSPSPPSPPPSSPPTimeline 2024 2034NeutrinosHiggs BosonDark MatterCosmic EvolutionDirect EvidenceQuantum I

286、mprintsAstronomy&AstrophysicsScience ExperimentsAdvancing Science and Technology through Agile ExperimentsScience EnablersIncrease in Research and DevelopmentASTAE PPPPPPLBNF/PIP-IIACE-MIRTSURF ExpansionACE-BR,AMFFigure 1 Program and Timeline in Baseline Scenario(B)Possible acceleration/expansion fo

287、r more favorable budget situationsScience DriversDEMONSTRATORNeutrinosHiggs BosonDark MatterCosmic EvolutionDirect EvidenceQuantum ImprintsFigure 2 Construction in Various Budget ScenariosScience Driverson-shore Higgs factoryNDelayedYYYYCR&DR&DR&DNNNNNNR&DR&DCYYYYYCR&DR&DR&DR&DNNNNYYYYYYYYCYR&DYYNNN

288、YYYNNoff-shore Higgs factoryACE-BRCMB-S4Spec-S5IceCube-Gen2G3 Dark Matter 1DUNE FD3test facilities&demonstratorACE-MIRTDUNE FD4G3 Dark Matter 2Mu2e-IIsrEDMSURF ExpansionDUNE MCNDMATHUSLA#FPF#Medium and large-scale US investments in new construction projects for possible budget scenarios.The projects

289、 are ordered in three budget brackets according to the number of“N”entries and then by approximate budget sizes.For the off-shore Higgs factory,test facilities&demonstrators,see Recommendation 6.See the caption of Figure 1 concerning the science drivers,and Section 8 for the rationale behind these c

290、hoices.N:NoIndex:Y:Yes R&D:Recommend R&D but no funding for projectDelayed:Recommend construction but delayed to the next decadeC:Conditional yes based on review P:Primary S:SecondarySSPPSPPPSPPPPPPSSSSSPPPPPPPPPPPSPSSPPPPPSPSPPSPPPSSLessScenariosBaselineMoreAstronomy&AstrophysicsUS Construction Cos

291、t$3B$13B$4001000M$100400M$60100M#Can be considered as part of ASTAE with reduced scopeDRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel 313Decipher the Quantum Realm DRAFT Exploring the

292、Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization Panel3:Decipher the Quantum Realm 333:Decipher the Quantum Realm 323.1Elucidate the Mysteries of Neutrinos 3.1.1 Science OverviewNeutrinos are the second most abu

293、ndant known particles in the universe and yet remain an enigma within the framework of the Standard Model.The observation of neutrino oscillations,and the consequent realization that neutrinos have mass,is one of the rev-olutionary discoveries of recent decades.Despite being the lightest of matter p

294、articles,the tiny mass of neutrinos challenges the standard paradigm of particle physics and has opened a compelling new domain of exploration within the quantum realm.Nature producesand we observeneutrinos in three different“flavors”:electron neutrino,muon neutrino,and tau neutrino.We understand ea

295、ch of these neutrino flavors to be a chimera,a mixture of states with different masses.According to quantum mechanics such a mixture will evolve,or oscillate,into another flavor as it travels.Neutrino oscillation processes have been extensively observed,and the admixture of neutrino mass states assi

296、gned to each flavor(mass mixing)and the differences between the neutrino masses have been measured.Yet the actual values of the neutrino masses remain unknown,and we are not yet sure how they are acquired.Various theoretical frameworks propose Atoms are the building blocks of matter,but what are the

297、 building blocks of atoms?For more than a century we have known that each atom is composed of electrons surrounding a heavy nucleus,bound together by the electromagnetic force.The nucleus is composed of protons and neutrons,which are themselves composed of quarks,bound together by the strong force.T

298、he building blocks of atoms are particles,and the forces that bind the building blocks are also described by particles.All known subatomic phenomena can be de-scribed by particles and their interactions,an amazing new concept in modern science.When we look deeper,we see that there is a rich landscap

299、e of quantum effects that rule the subatomic realm.The electron appears indivisible,yet its properties are affected by a quantum dance among all subatomic particles.The heaviest known subatomic particle is the top quark,which is surprisingly as massive as a gold atom.While the massless photons and g

300、luons mediate the electromagnetic and strong force respectively,the me-diators of the weak force,the W and Z bosons,are massive,blurring the distinction be-tween“force”and“matter”.The Higgs boson,the particle associated with the Higgs field that permeates the universe,gives mass to other particles.T

301、he Standard Model provides a unified,elegant picture of the subatomic realm that has withstood the most rigorous tests at LHC and KEK.Beautiful as this picture is,it does not yet account for the masses of the mysterious and mutable neutrinos,which oscillate into one another as they travel through th

302、e universe.Is the Standard Model the ultimate description of the quantum realm?Certainly not,which motivates the two science drivers under this theme for the next decade:Elucidate the Mysteries of Neutrinos.Neutrinos come in three types,or flavors,which undergo quantum oscillations.While the Standar

303、d Model can be augmented to accommo-date neutrino mass and oscillations,we do not know in which specific way to extend the model.Moreover,different extensions make vastly different predictions about the birth of the universe.We must further investigate the mysteries of neutrinos in order to explore

304、the deep connections between their physics and the Standard Model.Reveal the Secrets of the Higgs Boson.The discovery of the Higgs boson in 2012 was a major victory for the Standard Model.Subsequent investigations have revealed that the metastable vacuum in the Standard Model puts the universe on a

305、knife-edge of cosmic collapse.Determining the ultimate fate of the universe and looking for physics beyond the Standard Model motivates further scrutiny of the Higgs sector.DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle

306、Physics Project Prioritization Panel3.1.2 Ongoing Projects:NOvA,T2K,SBN,DUNE Phase I,PIP-IIOngoing accelerator-based experiments NOvA and T2K have pioneered electron neutrino and antineutrino appearance observations.They have introduced approaches to control systematic uncertainties as applied to co

307、mbined measurements of mass ordering and CP violation and other mass mixing parameters.A joint T2K and NOvA analysis of the two datasets is ongoing,and results obtained with the complete datasets may provide early indication of future discovery.Ongoing experiments also conduct interesting searches f

308、or phenomena beyond the Standard Model.Over the past decades neutrino oscillation searches at length/distance scales of 1 MeV/m have found a number of anomalous results:The liquid scintillator neutrino detector(LSND)anomaly,the reactor antineutrino anomaly,the MiniBooNE low-energy excess and the gal

309、lium anomaly.These anomalies have not been confirmed,and the reactor antineutrino anomaly has been recently resolved.The remaining phase space will be conclusively tested by the current short-baseline neutrino(SBN)program at Fer-milab.The SBN program is also crucial in maturing the liquid argon(LAr)

310、technology and analysis.SBN,T2K,NOvA,and other ongoing experiments also make measurements of neutrino interactions,which underpin our understanding of neutrino oscillation mixing(Recommendation 1c).The DUNE experiment consists of three elements:a far detector complex at SURF,a near detector complex

311、hosted at Fermilab,and a neutrino beam sent across the 1300 km distance between the two facilities.The program has achieved significant design and construction milestones,successfully scaling Liquid Argon Time Projection Chamber(LArTPC)technology and preparing the largest underground laboratory in t

312、he US(sched-uled for completion by 2025).For the first phase of DUNE,the far detector complex will comprise two 10 kt LArTPCs in an underground area designed to accommodate up to four modules.In this phase these detectors and a near detector facility will be illuminated by the worlds brightest neutr

313、ino beam,generated by the LBNF at Fermilab.The PIP-II accelerator upgrade currently under construction is central in enabling at least 1.2 MW proton beam operation during Phase I(Recommendation 1b).DUNEs comprehensive program of neutrino oscillation measurements sets the mass-ordering question as it

314、s first goal.Thanks to DUNEs long baseline and broad energy range of neutrinos that result in a strong separation between normal and inverted mass ordering scenarios,DUNE Phase I is expected to achieve a definitive measurement of the mass ordering within its first decade of operation.This result,whe

315、n combined with measure-ments made over shorter distances by experiments such as JUNO,probes nonstandard couplings to matter.These measurements,when combined with Hyper-Kamiokande and ongoing experiments,may clarify the nature of mixing or uncover where the three-flavor mixing model is incomplete.di

316、verse methods for neutrino mass generation,often introducing novel particles and in-teractions.Certain theories even require that neutrinos must be their own antiparticles that will naturally but surprisingly lead to lepton number violation and provide a necessary condition for the matter dominant u

317、niverse we observe now.Likewise,we have not definitively measured the ordering of the neutrino masses,i.e.is the neutrino mass state that has the smallest overlap with the electron neutrino the heaviest or the lightest?We refer to the case where the lightest neutrino has the largest overlap with the

318、 electron neutrino as“normal”ordering,because the mass spectrum of the neutrinos in this case follows the familiar mass spectrum of the quarks and charged leptons.The opposite,or inverted,ordering would be a consequential surprise.For instance,a new symmetry would likely be needed to account for why

319、 the two heavier neutrinos are so similar in mass.Neutrino mass ordering impacts efforts that seek to measure the neutrino masses and to understand how neutrinos acquire mass in the first place.Precision studies of neutrino oscillations can resolve important questions beyond neutrino mass ordering.I

320、s the lightest(or heaviest)neutrino state an equal combination of muon and tau neutrinos,which would hint at new symmetries?Is three-flavor mixing a complete description of all neutrino flavor transitions?Do antineutrinos oscillate differ-ently than neutrinos,namely is the charge-parity inversion(CP

321、)symmetry violated,and could this difference relate to the origins of matter-antimatter asymmetry in the universe?We do not fully understand why some fundamental forces respect the CP,while others violate it.For example,we have long had experimental evidence that interactions involving the weak forc

322、e do not conserve CP.Conversely,our description of interactions involving the strong force could provide a mechanism for CP violation,yet all measure-ments so far are consistent with the relevant parameter being zero.Theories that describe particular patterns of CP violation and conservation can be

323、connected to such questions as the nature of dark matter,or why a universe born with equal amounts of matter and antimatter developed into the overwhelmingly matter-dominated universe we observe today.It therefore makes sense to search for and measure CP violation in every context that we can.Neutri

324、nos have also opened a new view of astrophysical phenomena that can pro-vide unique probes of neutrino physics.The neutrino signal from the core collapse of a massive star in the Milky Way galaxy provides a window into neutrino flavor transitions and transport in a turbulent environment with high ne

325、utrino density.Such an environment cannot be simulated on Earth.Answering the outstanding questions in neutrino physics requires a blend of novel technologies and measurements made with exquisite precision.These may serve as bea-cons,illuminating the path toward unveiling novel interactions,particle

326、s,or symmetries within the universe.3:Decipher the Quantum Realm 353:Decipher the Quantum Realm 34DRAFT Exploring the Quantum Universe:Pathways to Innovation and Discovery in Particle PhysicsDRAFT Report of the 2023 Particle Physics Project Prioritization PanelTogether these upgrades more than quadr

327、uple the DUNE Phase I exposure to achieve 600 kt*MW*yr by the mid-2040s,the originally envisioned timescale.At this integrated exposure we expect statistical and systematic uncertainties to be roughly balanced,giving DUNE significant and unique discovery potential across the neutrino mixing landscap

328、e.With higher statistics,control of systematic uncertainties(such as those arising from the interaction of neutrinos and nuclei)becomes increasingly crucial.A more capable near detector(MCND),a gas target combined with a magnetic field and electromagnetic calorimeter,is indispensable for this purpos

329、e.In addition,by being exposed to the worlds most intense neutrino beam,it will create a unique laboratory for the discovery of novel particles and interactions,many of which could shed light on the nature of dark matter and possible hidden sectors.The opportunities opened by DUNE Phase II shine bri

330、ghtest when complemented by a strong theory effort.The interaction of neutrinos and nuclei represents a complex many-body quantum problem,and significant theoretical work is required to gain quantitative understanding at a subatomic or nuclear level.This work will further reduce systematic uncertain

331、ties.Similarly,theoretical models of new physics will help interpret any anomalies or surprises in DUNE data.In fact,new developments in theory can open up the science opportunities of new physics searches both at the near and far detectors,many of which are not directly related to neutrinos.3.1.4 F

332、uture Opportunities:DUNE FD4,the Module of Opportunity The advent of ACE-MIRT will enable rapid acquisition of beam neutrino statistics,allowing DUNE to achieve 600 kt*MW*yr without deploying a fourth detector module(FD4).This paves the way for an expanded physics program,featuring an upgraded,more

333、efficient detector with enhanced charge reconstruction capabilities.Such a detector would allow for full exploitation of the long baseline neutrino program.A more capable detector with significantly improved light collection,charge granularity,and high radiochemical purity would push the detector energy threshold down to MeV,or lower,while improving track and energy reconstruction.A range of alter