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New Physics at the LHC

New Physics at the LHC. Claudia-Elisabeth Wulz. Institute of High Energy Physics of the Austrian Academy of Sciences . Experimental environment. Students will work within the CMS Collaboration.

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New Physics at the LHC

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  1. New Physics at the LHC Claudia-Elisabeth Wulz Institute of High Energy Physics of the Austrian Academy of Sciences New Physics at the LHC

  2. Experimental environment • Students will work within the CMS Collaboration. • Almost 20 fb-1 of integrated luminosity of pp interactions are available (√s up to 8 TeV), 300 fb-1 are expected by 2021 (√s up to 14 TeV). • Experience of Vienna CMS group: triggering, tracking, reconstruction of tracks and vertices as well as of muons, b’s and t’s. • One thesis showcase is mainly about triggering, the other about searches for new physics in the field of SUSY. Connections between triggering and physics are an important aspect for both. New Physics at the LHC

  3. Motivation for New Physics • The main motivation for the LHC, after the discovery of a Higgs boson, is the search for new physics. • The Standard Model, though extremely successful, leaves many questions open. • It needs to be embedded in an overarching theory, but which theory is it? • Concrete predictions of experimental signatures for new physics exist for many models (SUSY, strong electroweak symmetry breaking, extra dimensions, etc.) New Physics at the LHC

  4. Scalar top quarks • and are expected to have large mixing, due to the large top Yukawa coupling. The lower mass eigenstate may be relatively light. • Most analyses so far have exploited the decay channels or • with as well as New Physics at the LHC

  5. Showcase 1 – Scalar tops decaying to charm • Production of in association with two b-jets in the stop-neutralinocoannihilation region . • In this case the branching fraction is close to 100%. LO QCD contribution LO electroweak contribution Signature: 2 b-jets and missing energy, no leptons Backgrounds: • Analysis strategies: • cut-based analysis • multivariate techniques as alternative • background estimates from data where possible New Physics at the LHC

  6. Motivation for an Upgraded Trigger System • The current trigger system has worked very well. It is designed for luminosities up to 1034 cm-2s-1, average number of pileup events of about 25, and a maximal Level-1 output rate of 100 kHz. • For the future, the physics potential of CMS must be maintained or extended, and aging hardware must not become an issue. Luminosity, centre-of-mass energy and pileup will increase. Example for improvement in triggering on scalar tops (e.g. through better transverse momentum estimates or pileup subtraction) New Physics at the LHC

  7. Showcase 2 – Muon trigger upgrade • Analysis-like, flexible trigger algorithms already at Level-1 with new FPGA’s: • e.g. boosted decision treepT assignment • more muon candidates than now, with higher precision in pT • muon isolation information • b-tagging of jet candidates through use of muon information. Currrentmuon trigger in the CMS cavern New Physics at the LHC

  8. Synergies within the DK and connections • Collaboration experiment – theory • A. Hoang (University of Vienna): QCD, SUSY • A. Rebhan (TU Vienna): QCD, SUSY • Theory groups (Institute of High Energy Physics): SUSY, QCD, new Dark Matter group (J. Pradler) • Development of trigger and reconstruction algorithms, data analysis in the fields of SUSY and other beyond the Standard Model physics • R. Frühwirth, M. Jeitler, J. Schieck (Institute of High Energy Physics) • H. Abele (TU Vienna) • Computing • Austrian Tier-2 GRID centre • International Collaborations • CERN and institutions worldwide New Physics at the LHC

  9. Thank you for your attention! New Physics at the LHC

  10. BACKUP New Physics at the LHC

  11. Added value • Students will work in a stimulating environment: • investigation of fundamental physics problems • world’s most powerful particle accelerator • large scientific community but human-sized research groups • international, multidisciplinary • Focus on research activities will shift to physics analyses, after long and important development work in triggering and tracking • Reinforcement of collaboration between theorists and experimentalists SUSY at the LHC SUSY at the LHC New Physics at the LHC

  12. SUSY limits from CMS New Physics at the LHC

  13. ATLAS direct stop limits New Physics at the LHC

  14. ATLAS direct stop limits in 0-lepton channel ATLAS-CONF-2013-024 New Physics at the LHC

  15. Stop to charm Alternative signature: monojet if New Physics at the LHC

  16. Projections for stop New Physics at the LHC

  17. CMS Trigger upgrade New Physics at the LHC

  18. Tail clipping The initial pT estimate of about 32 GeV is too large for the input Df(ME1-ME2) value (50f-units) according to the 5% tail fraction curve (shown in black). The initial 32 GeV estimate is substituted by the highest pT for which 50 f-units is below the 5% tail fraction curve, in this case 12 GeV. New Physics at the LHC

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