Institute for Anything of the University of Everything Claudia-Elisabeth Wulz New Physics at the LHC C.-E. Wulz (Institute of High Energy Physics) 1 Institute of High Energy Physics of the Austrian Academy of Sciences New Physics at the LHC

Experimental environment 2 C.-E. Wulz (Institute of High Energy Physics) n Students will work within the CMS Collaboration. n 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  ’s. n 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

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

Scalar top quarks 4 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC n and are expected to have large mixing, due to the large top Yukawa coupling. The lower mass eigenstate may be relatively light. n Most analyses so far have exploited the decay channels or with as well as

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

Motivation for an Upgraded Trigger System 6 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC Example for improvement in triggering on scalar tops (e.g. through better transverse momentum estimates or pileup subtraction) n The current trigger system has worked very well. It is designed for luminosities up to cm -2 s -1, average number of pileup events of about 25, and a maximal Level-1 output rate of 100 kHz. n 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.

Showcase 2 – Muon trigger upgrade 7 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC n Analysis-like, flexible trigger algorithms already at Level-1 with new FPGA’s: e.g. boosted decision tree p T assignment more muon candidates than now, with higher precision in p T muon isolation information b-tagging of jet candidates through use of muon information. Currrent muon trigger in the CMS cavern

Synergies within the DK and connections 8 C.-E. Wulz (Institute of High Energy Physics) n 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) n 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) n Computing Austrian Tier-2 GRID centre n International Collaborations CERN and institutions worldwide New Physics at the LHC

Thank you for your attention! 9 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC

BACKUP 10 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC

Added value SUSY at the LHC n 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 n Focus on research activities will shift to physics analyses, after long and important development work in triggering and tracking n Reinforcement of collaboration between theorists and experimentalists C.-E. Wulz (Institute of High Energy Physics) 11 New Physics at the LHC

SUSY limits from CMS 12 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC

ATLAS direct stop limits 13 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC

ATLAS direct stop limits in 0-lepton channel 14 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC ATLAS-CONF

Stop to charm 15 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC Alternative signature: monojet if

Projections for stop 16 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC

CMS Trigger upgrade 17 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC

Tail clipping 18 C.-E. Wulz (Institute of High Energy Physics) New Physics at the LHC The initial pT estimate of about 32 GeV is too large for the input  (ME1-ME2) value (50  -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  -units is below the 5% tail fraction curve, in this case 12 GeV.