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Searching for long-lived particles at the LHC: Third workshop of the LHC LLP Community

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500/1-001 - Main Auditorium (CERN)

500/1-001 - Main Auditorium

CERN

400
Show room on map
Albert De Roeck (CERN), Brian Shuve (SLAC National Accelerator Laboratory), Giovanna Cottin (National Taiwan University), James Beacham (Ohio State University (US)), José Francisco Zurita (KIT), Juliette Alimena (Ohio State University (US)), Martino Borsato (Universidade de Santiago de Compostela (ES)), Michelangelo Mangano (CERN), Nishita Desai (LUPM, Montpellier), Will Buttinger (CERN), Xabier Cid Vidal (Universidade de Santiago de Compostela)
Description

Following the successes of the LHC Long-Lived Particle (LLP) Workshops in April and October of 2017 -- and continuing the robust and rich tradition defined by prior workshops such as “LHC Searches for Long-Lived BSM Particles: Theory Meets Experiment", at U. Mass, Amherst, in November of 2015; “Experimental Challenges for the LHC Run II", at the Kavli Institute for Theoretical Physics in May of 2016; and the “LHC Long-Lived Particles Mini-Workshop" at CERN in May of 2016 -- the LHC LLP Community, composed of members of the CMS, LHCb, and ATLAS collaborations as well as theorists, phenomenologists and those interested in LLP searches with dedicated LHC detectors such as milliQan, MoEDAL, MATHUSLA, FASER, Codex-b, etc., convenes again to discuss the outcomes presented in the community white paper, assess the state of searches for long-lived particles beyond the Standard Model at the LHC, brainstorm about new ideas for LLP searches, and focus on the future of LLP searches in HEP, both at the LHC and for future detectors and projects.

The format will likely be similar to that of our previous workshops, i.e., a working-workshop, where we focus on discussion and collaboration, with any talks functioning to set the stage for that collaboration.

This workshop is unique, however, because after months of work by our community, the white paper is currently nearing completion.  Thus, while we will definitely feature a component devoted to a review of the content of the white paper, the focus of this workshop will be on the future:

  • What's next for LLP searches at the LHC?
  • What didn't we get to cover in the first white paper?
  • What recommendations for triggers and upgrade studies have arisen since we started this work?
  • How well do we really, quantitatively understand where our searches for prompt objects have sensitivity for LLPs, and how can we encourage the experimental collaborations to address this question comprehensively?
  • What about future detectors?
  • And what about new ideas for thinking critically about the ultimate sensitivity for LLP signatures / benchmark simplified models at the LHC and about what will be learned at future machines?


And yes, of course there will be at least one lightning round!  Please contact the organizers with your proposal or idea.

The first day of the workshop features collaborative sessions with the Re-interpretations workshop concluding that same day, also at CERN.

The agenda is taking shape now, but please register now!

Note that while we hope to see you in person at CERN, remote participation will indeed be available via Vidyo.  Please register whether you will participate in person or remotely and indicate so in your registration.

Registration
Registration for the third workshop of the LHC LLP Community
Register
Participants
152 View full list
  • Wednesday 16 May
    • 09:00 → 09:30
      Introduction to the LLP Community and Whitepaper 30m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
      Speakers: Brian Shuve (Harvey Mudd College), James Beacham (Ohio State University (US))
      Beacham_LHC_LLP_CERN_Intro_and_Goals_2018May16.pdf
    • 09:30 → 10:00
      Long-lived particles at the LHC: A theorist's perspective 30m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
      Speaker: Brian Shuve (Harvey Mudd College)
      LHC-LLP_Shuve.pdf
    • 10:00 → 10:30
      Coffee 30m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 10:30 → 11:30
      LLP search snapshots 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 11:30 → 12:45
      Material for re-interpretation - I 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
      • 11:30
        Re-interpretation of long-lived particle searches: Whitepaper recommendations 30m
        Speaker: Nishita Desai (LUPM, Montpellier)
        LLP-reinterpretation.pdf
      • 12:00
        Fast detector simulation for LLPs: Delphes and MA5 25m
        Speakers: Eric Conte (Universite de Haute Alsace (FR)), Eric Conte (Laboratoire de Physique Corpusculaire (LPC))
        MA5-LLP.pdf
      • 12:25
        Update on public tools for LLP recasts: Checkmate / Gambit discussion 20m
        Speakers: Anders Kvellestad (Nordita), Jong Soo Kim (IFT Madrid)
        LLP-CheckMATE.pdf
        LLPs_with_GAMBIT_Kvellestad.pdf
    • 12:45 → 14:00
      Lunch 1h 15m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 14:00 → 15:30
      Material for re-interpretation - II 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 15:30 → 16:00
      Coffee 30m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 16:00 → 18:00
      Contributed Talks 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
      • 16:00
        Dark photon interpretation of LHCb search 20m
        Speaker: Wei Xue (CERN)
        Slides
      • 16:20
        Reinterpretation of long-lived particles searches within SModelS 20m
        Speaker: Jan Heisig (RWTH Aachen University)
      • 16:40
        Freeze-in and LLPs 20m
        Speaker: Mr Bryan Zaldivar (LAPTh, Annecy)
        llp_freezein_zaldivar.pdf
      • 17:00
        Recasting the scotogenic FIMP 20m
        Speaker: Stefan Vogl (Max Planck Institute for Nuclear Physics)
        LLP.pdf
      • 17:20
        Novel signatures for long-lived particles at the LHC 20m
        Speaker: Ms Swagata Mukherjee (Rheinisch Westfaelische Tech. Hoch. (DE))
        Swagata_LLP.pdf
      • 17:40
        Long-lived neutrinos in the left-right symmetric model 20m
        Speaker: Goran Popara
        Popara_LLP2018.pdf
    • 18:00 → 19:00
      DIY welcome drink in CERN Restaurant 1 1h 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
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  • Thursday 17 May
    • 09:00 → 09:45
      Top-down theory overview and simplified models yielding LLPs 45m 40/S2-C01 - Salle Curie

      40/S2-C01 - Salle Curie

      CERN

      115
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      Speaker: Prof. David Curtin (University of Toronto)
      davidcurtin_MATHUSLA_physics_case_CERN_LHCLLPworkshop_40m_17may2018_v3_after_talk.key.pdf
    • 09:45 → 10:00
      White paper chapter 3 -- Experimental coverage of LLP signatures 15m 40/S2-C01 - Salle Curie

      40/S2-C01 - Salle Curie

      CERN

      115
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      Speaker: José Francisco Zurita (KIT)
      LLP_EXP_coverage_CERN.pdf
    • 10:00 → 10:30
      Elevator pitch session: Your idea goes here 40/S2-C01 - Salle Curie

      40/S2-C01 - Salle Curie

      CERN

      115
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      Convener: Will Buttinger (CERN)
    • 10:30 → 10:45
      Coffee 15m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 10:45 → 11:45
      Lightning round: Session 1 40/S2-C01 - Salle Curie

      40/S2-C01 - Salle Curie

      CERN

      115
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      • 10:45
        Neutrino reinterpretation and particle masses with displaced vertices 15m
        Speaker: Giovanna Cottin (National Taiwan University)
        LLP_Workshop_May2018.pdf
      • 11:00
        Singlet-Doublet Dark Matter Freeze-in: LHC displaced signatures 15m
        Speaker: Alberto Mariotti (VUB Brussels)
        SDFI_Mariotti_4.pdf
      • 11:15
        Discerning the left sneutrino LSP with displaced-vertex searches 15m
        Speaker: Iñaki Lara Pérez (UAM-CSIC)
        LLP_ILara.pdf
      • 11:30
        Long lived right-handed neutrinos, oscillations and leptogenesis 15m
        Speaker: Oliver Fischer (Unibas)
        LHC-LLP18_HeavyNeutrinoOscillations_Fischer.pdf
    • 11:45 → 12:10
      White paper chapter 5 -- Triggers and detector upgrades 25m 40/S2-C01 - Salle Curie

      40/S2-C01 - Salle Curie

      CERN

      115
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      Speaker: Yangyang Cheng (Cornell University (US))
      llp_upgrade_ycheng_051718.pdf
    • 12:10 → 13:40
      Lunch 1h 30m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
    • 13:40 → 15:00
      Dedicated LLP experiments: Session 1 503/1-001 - Council Chamber

      503/1-001 - Council Chamber

      CERN

      162
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      • 13:40
        MATHUSLA 20m
        Speaker: Mason Proffitt (University of Washington (US))
        MATHUSLA LLP Workshop.pdf
      • 14:00
        SHiP 20m
        Speaker: Federico Leo Redi (EPFL - Ecole Polytechnique Federale Lausanne (CH))
        redi_LLP_2018.pdf
      • 14:20
        SeaQuest 20m
        Speakers: Stefania Gori (University of Cincinnati (US)), Stefania Gori (Perimeter Institute/Cincinnati University)
        TalkLLP.pdf
      • 14:40
        MilliQan 20m
        Speaker: Chris Hill (Ohio State University (US))
        milliQan_LLP_CERN_051818.pdf
    • 15:00 → 15:20
      Coffee 20m 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
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    • 15:20 → 17:30
      Breakout working group sessions: Parallel and hands-on
      breakoutLLPSim.pdf
      JZ_Blue_Sky_Session_report.pdf
      LHC-LLP18-HNL_BreakoutSession_Summary.pdf
      • 15:20
        Breakout #1 2h 10m 42/R-014

        42/R-014

        CERN

        6
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        Geant4, Pythia, and the challenges of LLP simulation(-over-beers)

        Speaker: Will Buttinger (CERN)

        Simulating travelling rhadrons

        - 2 grids in the Whitepaper where the LLP carries SM (except weak) charge. We need to know how to simulate these.
        - Important to let G4 interact the rhadron because it can hadronize as it goes through all the material (travels through more than a bhadron because of lifetime) so cannot decide how to decay it before g4 does its thing (unlike bhadrons, as is done in evtgen, where assumption that bhadron wont change state is reasonable given lifetime/material).
        - G4 can decay slepton, but not things like rhadrons ...  need to use pythia.
        - Have been technical issues in being able to reinitialize pythia after G4 runs and make it decay an rhadron that’s given to it (Reported by Jennifer, Somewhat resolved by Steve?).
        - How do we pass configuration information from pythia->G4->pythia in this chain ... ATLAS moving away from HepMC, making it harder to do this in a unified way, each collaboration just deals with it themself?
        - The current mass spectrum ("generic" or "intermediate") used by ATLAS for rhadrons is a hacked-together incoherent(?) mess. Its a choice. Last update was 5 years ago, before that was 15 years ago. Store deltas (are masses relative to the input gluino state). Rather than adding up the constituent quark masses to get Rhadron mass in pythia, we should just specify the masses for each Rhadron. 
        - Regge model determines hadronic interactions - is what is in use in ATLAS atm. Not the same as “regge model” mass spectrum that is used in pythia6. CMS uses the "cloud model" for the hadronic interactions, which we hope is the same thing.
        - At the moment spin correlations are completely neglected - nobody can think of an important case where it matters.

        Simulating stopping rhadrons

        - At the moment ATLAS uses a simple stopping threshold criteria (Beta < A^(-2/3)). This doesnt simulate the deceleration of stopping rhadrons, which would occur as they drag ions along. 

        - Concern that efficiencies measured in stopping particle searches are overestimated (by factors of maybe 2, not 10-100). Would like to be able to simulate these correctly.

        Simulating quirks

        - Chris Hill made his argument for why quirks are basically non-existent (all but shortest string lengths were killed by fractional charge search).
        - Could reinterpret Heavy Stable Charged Particle searches in terms of (short length) quirks if we had a reliable simulation. But it's going to be driven by best effort, and effort seems lacking.

        Fast simulation

        - There was reasonable interest in understanding how far validity of fast simulation can go when it comes to LLPs (non-pointing tracks/photons etc).

         

        Action items

        - It is very important that each simplified model in the white paper that features long-lived interacting (SM-charged) particles should come with a corresponding description of the interaction model. Experts should be assembled to define/document for each case (rhadrons, HIP, monopole, ..) where relevent:

           - Particle mass spectrum
           - Particle fragmentation function
           - G4 interaction model
           - Other relevant parameters of the model (e.g. initial qluino/gluon fraction)

        - At very least there needs to be effort to compare/contrast what is currently done by ATLAS and CMS and LHCb to check for differences

        - Would like to call for studies on both sides that compare fast and full sim in LLP scenarios to try to quantify geometric/phase space where fast sim is reasonable

         

        Participants in discussion

        Zach Marshall (ATLAS)
        Larry Lee (ATLAS)
        Chris Hill (CMS)
        Steve Mrenna (CMS/Pythia)
        Jennifer Roloff (ATLAS)
        ...

      • 15:20
        Breakout #2 2h 10m 4/3-001

        4/3-001

        CERN

        18
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        Heavy Neutral Leptons

        Speakers: Carlos Vazquez Sierra (Nikhef National institute for subatomic physics (NL)), Daniele Trocino (Ghent University (BE)), Oliver Fischer (Unibas), Philippe Mermod (Universite de Geneve (CH))
        HNL breakout session.pdf
        IMG_2211.JPG
        IMG_2212.JPG
        IMG_2213_good.jpg
      • 15:20
        Breakout #3 2h 10m 503/1-001 - Council Chamber

        503/1-001 - Council Chamber

        CERN

        162
        Show room on map

        Blue-Sky Thinking / Go-Nuts / Brainstorming-Over-Beers / No-Idea-Too-Crazy

        Speaker: José Francisco Zurita (KIT)
        Blue_Sky_Session.pdf
    • 19:30 → 21:30
      Workshop dinner 2h 500/1-001 - Main Auditorium

      500/1-001 - Main Auditorium

      CERN

      400
      Show room on map
  • Friday 18 May
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