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62-481: In 2013, HEPAP was asked to convene a panel (the P5) to evaluate research priorities in the context of anticipated developments in the field globally in the next 20 years. Recommendations were to be made on the basis of three funding scenarios for high-energy physics: In May 2014, the first P5 report since 2008 was released. The 2014 report identified five "science drivers"—goals intended to inform funding priorities—drawn from

124-497: A better chance to see rare processes and improving statistically marginal measurements. Many different paths exist for upgrading colliders . A collection of different designs of the high luminosity interaction regions is being maintained by the European Organization for Nuclear Research (CERN). A workshop was held in 2006 to establish the most promising options. Increasing LHC luminosity involves reduction of

186-489: A decay volume of 10 m , which is 3 orders of magnitude higher than FASER and will increase the sensitivity range by 4 orders of magnitude. It will probe into the regime of dark photons , dark Higgs bosons , heavy neutral leptons , and weak gauge boson coupling. It will also have the subdetector FASERnu for neutrino and antineutrino observations. LHCb: LHCb will receive reduced aperture central vacuum chambers during LS2. The Vertex Locator (VELO) detector which measures

248-506: A factor of 10. However, at the LUMI'06 workshop, several suggestions were proposed that would boost the LHC peak luminosity by a factor of 10 beyond nominal towards 1⋅10  cm ⋅s . The peak luminosity at LHC was limited due to the cooling capacity of its triplet magnets and secondly due to the detector limits. The resultant higher event rate posed challenges for the particle detectors located in

310-867: A full professor of physics in 2000. He is the founding director of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) at the University of Tokyo since 2007. In addition, he has been a visiting scientist at CERN since 2016. In 2013, he was elected to the American Academy of Arts and Sciences and was chosen as a fellow of the American Physical Society . In October 2014, he delivered an invited lecture titled "Science for Peace and Development" at

372-408: A muon collider is ultimately feasible, the road toward it leads from current Fermilab strengths and capabilities to a series of proton beam improvements 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.” The cost of a 10 TeV muon collider

434-683: A new program entitled “Advancing Science and Technology through Agile Experiments" (ASTAE). This responds to calls by the community to support “small” experiments, which particle physics defines as costing less than $ 50M in total. Unlike other programs, this recommendation called for $ 35M/year to be invested in ASTAE. This recommendation again reflected the concerns identified by the International Benchmarking Panel. The American Physical Society, Fermi National Accelerator Laboratory and SLAC Laboratory organized endorsements by

496-576: A poor metric for measurement of scientific impact. Two points made in the report are especially relevant to P5 considerations: 1) The US should prioritize being a "partner of choice" and 2) The US requires a range of project sizes and goals to maintain a healthy "scientific ecosystem". The primary outcome of the benchmarking report was that "the U.S. is not always viewed as a reliable partner, largely due to unpredictable budgets and inadequate communication, and that shortcomings in domestic HEP programs are jeopardizing U.S. leadership." The report highlighted that

558-507: A reporter from Physics Today : "There are big issues people didn’t discuss." Panel chair Hitoshi Murayama has expressed awareness of this problem, saying that "community buy-in is key" for the success of the P5 report. The membership of the 2023 P5 was announced in December 2022, with Hitoshi Murayama of the University of California, Berkeley as head. See the official page . Similar to 2014,

620-554: A smaller diameter. The tracking system and the time projection chambers will be upgraded along with a new faster interaction trigger detector. ATLAS: The liquid argon calorimeter at ATLAS will be upgraded to identify the electrons and photons more effectively. The main readout electronics of the calorimeter will be completely replaced to let the detector identify rare particle interactions. These changes are planned for Long Shutdown 3 (LS3) of LHC. CMS: CMS will carry out numerous upgrades to its inner tracking system,

682-705: A year-long discussion within the particle physics community. These science drivers are: In pursuit of the five science drivers, the 2014 report identified three "high priority large category" projects meriting significant investment in the FY2014–2023 period, regardless of the broader funding situation: the High Luminosity Large Hadron Collider (a proposed upgrade to the Large Hadron Collider located at CERN in Europe);

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744-410: Is also a possibility for HL-LHC to detect BSM phenomena such as baryogenesis , dark matter , answers to the flavour problem , neutrino masses and insights into the strong CP problem . The upgrades to the heavy-ion injectors are also in progress and would bring up even more opportunities to observe very rare phenomena and to search for BSM physics. The HL-LHC project was initiated in 2010, and

806-486: Is an upgrade to the Large Hadron Collider , operated by the European Organization for Nuclear Research (CERN), located at the French-Swiss border near Geneva . From 2011 to 2020, the project was led by Lucio Rossi . In 2020, the lead role was taken up by Oliver Brüning. The upgrade started as a design study in 2010, for which a European Framework Program 7 grant was allocated in 2011, with goal of boosting

868-574: Is to have a high efficiency and highly reliable machine which can deliver the required integrated luminosity. Major goals of HL-LHC thus belong to the following five categories; improved Standard Model measurements, searches for beyond the Standard Model (BSM) physics, flavor physics of heavy quarks and leptons , studies of the properties of the Higgs boson , and the studies of QCD matter at high density and temperature. Measurements of

930-868: The Headquarters of the United Nations in an event honoring the 60th anniversary of CERN . Professor Murayama is involved in the KamLAND neutrino experiment at the Kamioka Observatory , an underground neutrino detection facility near Toyama , Japan . The KamLAND collaboration won the Breakthrough Prize in Fundamental Physics in 2016. In 1998, Murayama, Gian Giudice , Markus Luty and Riccardo Rattazzi discovered " anomaly mediated supersymmetry breaking ,

992-896: The International Linear Collider (a proposed electron - positron collider, likely hosted in Japan); and the Long Baseline Neutrino Facility (an expansion of the proposed Long Baseline Neutrino Experiment (that was renamed the Deep Underground Neutrino Experiment ), to be constructed at Fermilab in Illinois and at the Homestake Mine in South Dakota). In addition to these large projects,

1054-773: The Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo . Born in Japan in 1964, Murayama obtained his B.Sc. in Physics from the University of Tokyo in 1986. He completed his Ph.D. in Tokyo in 1991. In 1993, he moved to the US to join the Lawrence Berkeley National Laboratory as a post-doctoral research fellow. In 1995, he was appointed as an associate professor in University of California, Berkeley , where he became

1116-428: The heavy-ion sector, the integrated luminosities of 13 nb and 50 nb will be delivered for lead-lead and proton-lead collisions , respectively. The inverse femtobarn (fb ) unit measures the time-integrated luminosity in terms of the number of collisions per femtobarn of the target's cross-section . The increase in the integrated luminosity for the aforementioned major LHC experiments will provide

1178-726: The 1993 cancellation of the Superconducting Super Collider and the sudden 2008 termination of the B physics program at the Stanford Linear Accelerator Center, and the abrupt end of the TeVatron program at Fermilab followed by the immediate dismantling of the accelerator have caused the international community to lose confidence that the US will complete projects. Without addressing the DUNE project directly, this recommendation pointed to

1240-423: The 2023 P5 members are all particle and accelerator physicists; no members specialize in project management. This places the committee in a good position to evaluate responses to the "nightmare scenario." However, this makes it difficult for the members to assess whether the information on cost and schedule provided to the committee has a sound basis. That lack of expertise may explain how the 2014 P5 failed to foresee

1302-474: The CMS and ATLAS detector. A ten-year-long joint project between CERN, Brookhaven National Laboratory , Fermilab , and Lawrence Berkeley National Laboratory known as United States Department of Energy LHC Accelerator Research Program (US–LARP) successfully built and tested such quadrupole magnets. 20 inner triplet quadrupoles are in the production phase at CERN and in the US. Dipole magnets: For inserting

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1364-534: The DUNE Phase II upgrades to keep the project funding on track to begin data-taking in 2031. Despite the issues with DUNE, P5 recommended initiating work on a new megaproject called a muon collider. Accelerating and colliding muons for particle physics studies offers theoretical advantages over an electron-positron collider, but represents an untested and challenging new direction from a practical standpoint. The report states: “Although we do not know if

1426-541: The HL-LHC accelerator requirements, superconducting power transmission lines made of magnesium diboride (MgB 2 ) will be used to transmit the current of about 100,000 amperes. As part of the HL-LHC, significant changes will be made to the proton injector. The beams that come to LHC are pre-accelerated by following 4 accelerators. All four of these accelerators, together known as the Injectors will be upgraded through

1488-525: The Higgs boson and understanding its connection to the electroweak symmetry breaking remains the primary goal. In the domain of flavour physics; LHCb, ATLAS and CMS together will test the unitarity of the Cabibbo–Kobayashi–Maskawa matrix , and ATLAS and CMS will measure the properties of the top quark , the fermion with the largest known mass and largest Yukawa coupling . HL-LHC will also add to

1550-628: The LBNF/DUNE cost-and-schedule crisis, and will make it difficult for the 2023 P5 to head off an "SSC scenario." Regina Rameika from the Department of Energy Office of Science summarized the P5 charge in a presentation to the High Energy Physics Advisory Panel on Dec. 8, 2022. The charge asked P5 to: The priority of projects is being considered within two funding scenarios from the Department of Energy (DOE) and

1612-544: The LHC Injector Upgrade (LIU) project during the Long Shutdown 2 (LS2). The LIU is responsible for delivering beams of very high brightness to HL-LHC. The proton injectors will be upgraded to produce proton beams with double the original luminosity and 2.4 times the brightness . The replacement of Linear Accelerator 2 (Linac2 - which delivered the proton beams) with Linear Accelerator 4 (Linac4)

1674-539: The LHC Run-3. The upgrade plan for SND at HL-LHC is to continue developing the detector with the aim of improving the statistics of collision events, and expand its pseudorapidity range for studies of heavy-quark production and neutrino interactions. TOTEM : The TOTEM -CMS collaboration which has been operating the Proton Precision Spectrometer (PPS) since 2016, will measure

1736-520: The National Science Foundation (NSF). The first, which was described by physicists as "grim", envisions a 2% increase per year of the high energy physics budgets for DOE and NSF. The second assumes full funding from the 2022 CHIPS And Science Act and a 3% increase per year to DOE and NSF HEP. P5 is asked to consider operating costs, including the rising cost of energy to run accelerators. Throughout 2023, P5 received input from

1798-617: The P5 Town Halls. In December 2023, the 2023 P5 report was released. The proposals contained therein were intended to help better understand some of the current concerns of particle physics, including challenges to the Standard Model , and involve studies primarily dealing with gravity , black holes , dark matter , dark energy , Higgs boson , muons , neutrinos , and more. The 2023 P5 report identified three science drivers, each with two experimental approaches: “Decipher

1860-577: The P5 report strategy" and "P5 was wildly successful." From 2016 to 2020, the High Energy Physics (HEP) budget grew from less than $ 800 million to more than $ 1 billion. However, members of the HEP community were concerned because the increased funding went primarily toward projects, while funding for core research and technology programs, which was also supported by P5, declined from $ 361 million to $ 316 million. In 2020, an assessment of progress of

1922-527: The P5-defined program produced by the High Energy Physics Advisory Panel (HEPAP) concluded: "While investments over the past 5 years have focused on project construction, it will be fundamentally important to balance the components of the HEP budget to continue successful execution of the P5 plan. Operations of the newly constructed experiments require full support to reap their scientific goals. The HEP research program also needs strong support to fully execute

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1984-845: The Quantum Realm” through “Elucidat[ing] the Mysteries of Neutrinos” and “Reveal[ing] the Secrets of the Higgs Boson.” “Explore New Paradigms in Physics” though “Search[ing] for Direct Evidence of New Particles and Pursu[ing] Quantum Imprints of New Phenomena.” “Illuminate the Hidden Universe” through “Determin[ing] the Nature of Dark Matter” and “Understand[ing] What Drives Cosmic Evolution.” The recommendations that followed

2046-567: The accelerator's potential for new discoveries in physics. The design study was approved by the CERN Council in 2016 and HL-LHC became a full-fledged CERN project. The upgrade work is currently in progress and physics experiments are expected to start taking data at the earliest in 2028. The HL-LHC project will deliver proton-proton collisions at 14 TeV with an integrated luminosity of 3 ab for both ATLAS and CMS experiments, 50 fb for LHCb , and 5 fb for ALICE . In

2108-871: The beam intensity will decrease due to the burn-off of the circulating proton beams inside the collider. Maintaining the intensity at a constant level throughout the lifespan of beam is thus a major challenge. Nevertheless, plan is to at least have a system that would allow beam focusing or the concentration of the beams before the collision to remain constant. Cryogenics: Implementation of HL-LHC would require larger cryogenic plants, plus larger 1.8 Kelvin refrigerators, along with sub-cooling heat exchangers. New cooling circuits are also to be developed. The majority of these upgrades are for interaction points, P1, P4, P5, and P7. While P1, P4, and P5 will receive new cryogenic plants, P7 will have new cryogenic circuits. Machine protection and collimators: The collimators are responsible for absorbing any extra particles that deviate from

2170-424: The beam size at the collision point, and either the reduction of bunch length and spacing, or significant increase in bunch length and population. The maximum instantaneous luminosity increase of the existing nominal LHC luminosity (1⋅10  cm ⋅s ) is about a factor of 4 higher than the LHC's performance at its peak luminosity of 2⋅10  cm ⋅s , unfortunately far below the LHC upgrade project's initial ambition of

2232-512: The central-exclusive production events at the HL-LHC with an upgraded version of the near-beam PPS. Hitoshi Murayama Hitoshi Murayama ( 村山斉 ) is a Japanese-born physicist with notable contributions in the fields of particle physics and cosmology . He is currently a professor at the Center for Theoretical Physics at the University of California, Berkeley , and was the Director of

2294-464: The collision areas. Through the ongoing upgrades, HL-LHC's peak luminosity is expected to be 5⋅10  cm ⋅s and would most likely be pushed to 7.5⋅10  cm ⋅s . The HL-LHC upgrade being applicable to almost all major LHC experiments has a wide range of physics goals. Increasing the number of collisions to 140—each time the proton particle beams meet at the center of the ATLAS and CMS detectors—from

2356-499: The community of potential abrupt cancellations of ongoing particle physics projects, as flagged by the Benchmarking Panel. The P5 report sought to control the narrative of the DUNE project, which has seen an explosion in cost between the 2014 and 2023 P5 reports and is now lagging behind the competing HyperKamiokande project that will turn on in 2027. P5 offered compromises on beam power for DUNE Phase I and reductions of

2418-489: The community of the P5 report. As of January 15, the number of endorsers was 2602 US scientists. Among the endorsers, 37% were tenured faculty level or laboratory scientists, 9% were at the untenured faculty or laboratory scientist level, 16% were postdoctoral fellows, 20% were graduate students, and the remainder were other categories. The geographic distribution of the endorsements heavily favored Illinois, home of Fermilab, and California, home of SLAC. Only six months after

2480-485: The community through meetings that included invited talks and requested talks in a "town hall" format. Four meetings were held at national laboratories. Two virtual town halls were also held. The topics of the meetings covered physics goals across the range of topics defined by the Snowmass Study, as well as the balance of university- and laboratory-based research, opportunities for early early career scientists, and

2542-402: The crab cavities is to tilt and project the beams in the required direction. This tilting maximizes the overlap between the colliding bunches, leading to an increase in the achievable instantaneous luminosity. ATLAS and CMS together will have 16 crab cavities; which will give transverse momentum to the beams to increase the collision probability. Beam optics: As per the current HL-LHC design

Particle Physics Project Prioritization Panel - Misplaced Pages Continue

2604-440: The current number of 30, will open a number of new avenues for observing rare processes and particles. The boost in the integrated luminosity , or evidently the larger collision event datasets that would be accumulated through HL-LHC in case of all the LHC experiments, is the most significant aspect towards achieving the goals described below. The motivation for the construction of large underground infrastructure at HL-LHC therefore,

2666-474: The field that P5 must address: Along with these major issues, P5 also faces a field that is less unified than in 2014, as was emphasized by the title of the Scientific American report on Snowmass 2021 outcomes: "Physicists Struggle to Unite around Future Plans." Some members of the field have expressed that the pressure to project a unified opinion is stifling debate, with one physicists telling

2728-472: The following has been the timeline till 2020, followed by the tentative future stages. 2010: HL-LHC was established at CERN as a design study. 2011: The FP7 HL-LHC design study was approved and started. 2014: The first preliminary report on the design study was published. 2015: Budget and schedule along with technical design report was made available. 2016: CERN Council approved the HL-LHC project with its initial budget and schedule. Followed by which

2790-765: The hardware parts consisting of components and models were validated. Between 2018 and 2020: The prototypes were tested and final Technical Design report was published. The underground excavation work was also carried out. Although the civil engineering work and prototyping process would continue till the end of 2021. Between 2019 and 2024: The construction and testing of hardware parts is planned. 2021-2023: All surface bindings would be delivered. 2022-2024: The inner triplet string will be installed followed by its operation test. 2025-2027: New magnets, crab-cavities, cryo-plants, collimators, superconducting links, ancillary equipment, and absorbers are planned to be installed. If all above planned activities are completed according to

2852-437: The joint-agency CMB-S4 project, despite strong protest from the P5 leadership and appeals from the 500-person, international team. The IceCube-Gen2 project, planned to begin installation in the latter 2020's, may suffer delays due to the infrastructure renovations. High Luminosity Large Hadron Collider The High Luminosity Large Hadron Collider ( HL-LHC ; formerly referred to as HiLumi LHC , Super LHC , and SLHC )

2914-404: The knowledge of parton distribution functions (PDFs) by measuring several Standard Model processes with the jets, top quarks , photons and electroweak gauge bosons in their final state. The jet and photon production in the heavy ion collisions forms the basis of QCD perturbation theory probes, and HL-LHC will measure this at very high energy scales. Owing to these high energy collisions, there

2976-552: The most conservative of the funding scenarios considered would endanger the ability of the U.S. to host a major particle physics project while maintaining the necessary supporting elements. A goal of the 2014 P5 exercise was to provide Congress with a science-justified roadmap for project funding. Five years later, in 2019, the Department of Energy Office of Science declared: "Congressional appropriations reflect strong support for P5. Language in appropriations reports have consistently recognized community’s efforts in creating and executing

3038-564: The need for public outreach. In Autumn 2023, the P5 Panel received input from the HEPAP International Benchmarking Subpanel, headed by Fermilab scientists. This report is one in a series of evaluations of DOE supported science in an international context. Differences between high energy physics and the rest of the physics community are apparent in the report. For example, the report that citations are

3100-444: The new collimators , two of the LHC's dipole magnets will have to be replaced with smaller ones. They would be stronger (11 tesla) than LHC's dipole magnets (8.3 tesla) and be more powerful in bending the beam trajectories. As of now six 11 T dipoles are in the production phase. These magnets would probably be installed only after HL-LHC is fully implemented, although the final decision is yet to come. Crab cavities: The function of

3162-401: The original beam trajectory and can potentially damage the machines. The higher luminosities are bound to generate such highly energetic particles. HL-LHC design thus contains ways to prevent damages by replacing 60 out of 118 collimators and adding about 20 new ones. The upgraded collimators will also have lower electromagnetic interference with beams. Superconducting power lines: To meet

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3224-497: The plan, throughout the construction, operations, and data analysis phases of the experiments, and to lay a foundation for the future." As of 2022, several of the "Large Projects" identified as priorities by the 2014 P5 had fallen considerably behind schedule or been affected by cost gaps, including: The P5 process occurred in spring 2023 and was informed by the outcomes of the 2021 Snowmass Process finalized in summer 2022. The Snowmass 2021 study identified two existential threats to

3286-417: The potential negative impact on international cooperation if DUNE were abruptly curtailed by P5. A second major recommendation of the benchmarking report focused on the need to maintain a program of projects at all scales, from small to large, and that are chosen to specifically enhance areas in which the US technology is lagging, such as in accelerator physics. This echoed calls from the community expressed in

3348-443: The primary and displaced vertices of short-lived particles will be enhanced to meet the increased radiation and particle interaction rates. MoEDAL: For LHCs Run-3 MoEDAL will implement a new sub-detector called MoEDAL's Apparatus for the detection of Penetrating Particles (MAPP). For HL-LHC MAPP-1 would be upgraded to MAPP-2. Scattering and Neutrino Detector (SND): SND and will begin its first operation only in 2022, during

3410-468: The release of the 2023 P5 report, the first and sixth priority new projects, CMB-S4 and IceCube-Gen2, faced major setbacks from a call by NSF to immediately address the urgent need to update the South Pole Station infrastructure. In response, NSF halted the installation of new projects until end of the 2020's. Lack of near-term access to infrastructure at the pole led NSF and DOE to cancel

3472-595: The report identified numerous smaller projects with potential for near-term return on investment, including the Mu2e experiment, second- and third-generation dark matter experiments, particle-physics components of the Large Synoptic Survey Telescope (LSST) , cosmic microwave background experiments, and a number of small neutrino experiments. The report made several recommendations for significant shifts in priority, namely: The panel stressed that

3534-583: The statement of goals reflected the recommendations heard during the Snowmass process and those of the International Benchmarking Panel, discussed above. In particular, Recommendation 1 stated “As the highest priority independent of the budget scenarios, [funding agencies must] complete construction projects and support operations of ongoing experiments and research to enable maximum science.” This reflects concerns throughout

3596-487: The timeline, HL-LHC would be able to start its physics operation in 2028. The following upgrades to machine systems forms the core of the new HL-LHC. Quadrupole magnets: The strong magnets along with the huge rings are a necessary aspect of LHC's functionality. HL-LHC will have quadrupole magnets with the strength of 12 tesla as opposed to 8 tesla in LHC. Such superconducting magnets made up of inter-metallic niobium-tin (Nb 3 Sn), compound would be installed around

3658-430: The trigger system, the calorimeter, and the muon detection systems during Long Shutdown 2 (LS2) and LS3. These changes are based on the expected pile-up densities and increase in radiation due to the higher luminosity. Similar changes are also planned for the ATLAS experiment. FASER-2: LHC's FASER experiment will undergo several upgrades and be turned into FASER-2 to fully utilize HL-LHC's capabilities. It will have

3720-555: Was achieved in 2020. The Linac4 is a 160 MeV linear accelerator and delivers H beams with twice the beam brightness compared to its older counterparts. LIU also upgraded the cesiated radiofrequency-plasma H ion source that feeds Linac4. The challenge here was to have a high current, low emittance source beam. Heavy-ion injector upgrades through the upgrades to the Low Energy Ion Ring (LEIR) and Linac3 are also being designed. The source extraction system of Linac3

3782-607: Was not estimated in the report. The report offered a new emphasis on cosmology and astrophysics as a branch of particle physics. P5 placed the $ 800M CMB-S4 experiment at the top of the list of new projects. The report also emphasized the importance of the planned expansion of the IceCube neutrino detector in Antarctica, recommending funding for this new project in any budget scenario. In a recommendation with an unusual level of specifics regarding its implementation, P5 introduced

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3844-580: Was re-designed, and by the end of LS2 it successfully increased the extracted source beam intensity by 20%. To handle the increased luminosity, number of simultaneous particle interactions, massive amount of data, and radiation of the HL-LHC environment, the detectors will be upgraded. ALICE: The upgrade will increase the lifetime of the Tile Calorimeter (TileCal), which is a hadronic calorimeter sensitive to charged particles, by 20 years. The beam pipe at ALICE will also be replaced by one with

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