European Particle Physics Advisory Panel Community Meeting Insights

Particle Physics Advisory Panel Community Meeting Input to European Strategy Discussion Session

Process Today wide discussion. Hope at least to narrow down options to put forward. Produce start of draft writeup. Further meeting scheduled for 20thSept. At B ham. Meeting style & content to be influenced by today s discussion. Initial draft available prior to meeting in time for comment before 20th. Scope for additional meetings if we decide useful today. Deadline for submission 18 December 2018 Today wish to record discussion. (need your agreement) Enable those not able to come to send in comments. 16th July 2018 2

Next large collider? LHC HL-LHC ?? Do we want to back a next large scale collider project? Do we want to back one project a sequence of projects be non committal leave options open - Possibly define decision making process to occur during the next few years What do we want at CERN? Focus on one future option? Continue with CLIC? R&D sequence ? ?? 16th July 2018 3

Do we have to choose a top priority? If so what should Particle Physics Flagship be? At CERN what project? Not at CERN then where? - What does this mean for CERN? What we do in the next few (~6-7) will set scene for next big project. 2013 output document (d) To stay at the forefront of particle physics, Europe needs to be in a position to propose an ambitious post-LHC accelerator project at CERN by the time of the next Strategy update, when physics results from the LHC running at 14 TeV will be available. 16th July 2018 4

What information would help with arriving at decision? If feel not enough information what information would we like? 16th July 2018 5

2012 document submitted Recommendations: The highest priority is to capitalise on the investment made in the LHC by exploiting the scientific capabilities of the GPDs with LHC operations at up to 14 TeV collision energy. Investment should be made in accelerator and GPD upgrades to enable exploitation of the full potential of the LHC. Investment should continue to be made in the Grid computing facilities, physics modelling and simulations needed to support the greatly increasing data storage, handling, processing and analysis requirements. The options for next-generation collider facilities should be thoroughly reviewed in light of LHC results, and their pursuit coordinated globally. A timely decision should be taken on optimal next-generation collider facilities for exploitation of LHC discoveries. Europe should develop a coherent strategy to either host the next-generation facility or to participate in a facility built elsewhere. Europe should invest in the accelerator and detector technology developments needed to realise these facilities. 16th July 2018 6

Flavour physics Quarks If e.g. FCC built will have flavour physics capability. Enhances reason for building. Which areas of flavour physics do we wish to see pursued? List of anomalies (see slide). Other machines Flavour would like to support? Specific (fixed target) experiments. Generally support approach? Particular recommendations? CERN role? 16th July 2018 7

Beyond collider effort A lot of ideas here. Workshop Nov 2017 https://indico.cern.ch/event/644287/timetable How should this effort be steered (or not)? How should CERN support the effort? Does the UK have particular directions in which we want to steer this activity? 16th July 2018 8

2013 document - Flavour physics Recommendation: The highest priority is to fully exploit the capabilities of the current LHCb detector so as to maximise its scientific output, especially in probing BSM physics. In addition, investment should be made in the LHCb upgrade to enable full exploitation of the LHC flavour physics potential. Precision experiments in the bottom, charm, kaon, tau and muon sectors that bring complementarity and breadth to the global physics programme should be pursued, along with the associated theoretical work to maximise their impact; global coordination of national- or regional-scale programmes would be desirable. 16th July 2018 9

2012 PPAP document - Neutrinos Recommendations: Europe should develop a coherent strategy to either host the next generation long- baseline neutrino oscillation project or to participate in a global project. Dedicated neutrinoless double beta decay experiments should be pursued; global coordination of national- or regional-scale programmes would be desirable. Europe should pursue a programme of R&D into the construction of a very large scale Liquid Argon detector. Europe should continue to play a leading role in accelerator R&D in high power neutrino beams. 16th July 2018 10

2012 PPAP Document Non-accelerator Recommendations: A coordinated strategy for coherent European involvement in tonne-scale direct dark matter search experiments and efforts towards directional capability should be pursued on both the regional and global scales. Precision dipole moment search experiments should be pursued. 16th July 2018 11

2012 Document - Accelerator and detector R&D Recommendation: In order to promote the long-term vitality of experimental particle physics it is essential for Europe to invest in R&D on advanced technologies for both future accelerators and detectors at the energy and intensity frontiers. 16th July 2018 12

List of flavour experiments Many flavour experiments on small to medium scale Electron EDM (several experiments)* Neutron EDM (several experiments)* g-2* MUonE (mu-e scattering to reduce theory uncertainty on g-2) Mu2e, COMET/PRISM (mu + N -> e + N)* MEG, MEG-II (mu -> e gamma) Mu3e (mu -> 3e)* NA62 (K+ \to pi+ nu nu main mode)* KOTO (KL \to pi0 nu nu man mode SHiP* CELO-c* BES-III* Super tau-charm factory Belle-II - - - - - - - - - - - - - - 16th July 2018 13

Anomalous magnetic moment of the muon (g - 2) b s mu+ mu- angular distributions b s mu+ mu- differential branching ratios Lepton flavour non-universality, electrons vs. muons Lepton flavour non-universality, muons (and/or electrons) vs. taus Proton electric charge radius 16th July 2018 14

Anomalous magnetic moment of the muon (g - 2) - BNL (2004) 3.5-4 sigma from SM - g-2 taking data now - New measurement of fine structure constant (DOI:10.1126/science.aap7706) gives a new value of (g_e - 2) that is ~2.5 sigma from SM b s mu+ mu- angular distributions - Mostly P5 in Bd \to K* mu+ mu- at low invariant mass of the muon pair - P5 is a parameter describing the angular distribution, supposedly theoretically robust. b s mu+ mu- differential branching ratios - 2 - 3 sigma below SM for low invariant mass of the muon pair - Discrepancy varies but is present in several modes Lepton flavour non-universality, electrons vs. muons - Ratio of branching ratios of B \to K(*) l+ l-, comparing electron and muon modes - R(K) ~ 2.6 sigma from SM - R(K*) 2.1-2.5 sigma from SM - Updates and other R in progress. Lepton flavour non-universality, muons (and/or electrons) vs. taus - Ratio of branching ratios of B \to D(*) l+ nu, comparing muon and tau modes - Combined R(D*) and R(D) results are ~4 sigma from SM Proton electric charge radius - Discrepancy ~3.3 sigma between the charge radius from electron scattering and muonic hydrogen spectroscopy 16th July 2018 15

Dark Matter Going to larger experiments. What does the UK want to back? Does the next generation size have implications for organization? What does this mean (if anything) for CERN? Physics driver (mass objective) significant for experiment structure. What does this imply for strategy? 16th July 2018 16

CERN Last time CERN had clear future role CERN future not obvious, what do we want? CERN annual subscription UK contribution 178 M SF (15.8%) General R&D would we like CERN to do anything differently. E.g. RDXXX programme. Revamp? 16th July 2018 17

Precision physics Do we wish to back a specific project? If so which one? What should CERN s role be? 16th July 2018 18