Institute for Anything of the University of Everything

Claudia-Elisabeth Wulz

SUSY at the LHC

Search for Supersymmetry Signals at the LHC

C.-E. Wulz (Institute of High Energy Physics) 1

Institute of High Energy Physics of the Austrian Academy of Sciences

Motivation

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We know that the Standard Model of particle physics must be extended

Supersymmetry is such a possible extension, which can be embedded in higher-ranking theories

Detailed predictions of experimental signatures at the TeV scale exist

Searches can be performed throughout the entire lifetime of the LHC

SUSY at the LHC C.-E. Wulz (Institute of High Energy Physics)

Experiment

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Data from the CMS experiment will be used. By now more than 1 fb-1 of integrated luminosity are

available. By the end of 2011 3 to 4 fb-1 are expected. The Vienna CMS groups have particular experience in

triggering, tracking, recontstruction of tracks and vertices as well as of muons, b’s and t’s.

Research Goals

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Detect deviations from the Standard Model through inclusive analyses

Contribute to determine if a signal can be SUSY or not

Identify SUSY particles and determine their parameters, measure production cross-sections and branching fractions

In parallel: optimize/develop trigger strategies for all analyses

Now

Beginning ofLHC Phase 2

(≈2020)

Use generic signatures to detect deviations from the Standard Model

Methodology - generic signatures

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Current focus: search in the jets + missing ET + single muon channel

DKPI theses: • exploit jets + missing ET + single electron channel• exploit heavy flavor content of events

Leptonic topologies• Single lepton• Same-sign di-leptons• Opposite-sign di-leptons• Tri-leptons• Di-leptons + photon

Hadronic topologies• Exclusive n-jet• Inclusive ≥3 jet• Photon + missing ET

Methodology - simplified models

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Use simplified models

Example: on-shell effective theories (OSETs)• models based on bottom-up approach

• templates describing particle spectra and decay chains• OSETs can be used to tune and interpret searches in a more model-

independent way and to serve as interface between theory and experiment

Methodology – specific searches

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Use specific event signatures and models

Two possible, complementary approaches:• perform cut-based analysis• use multivariate techniques

Example: scalar top production in association with two b-jets in the coannihilation region within the Minimal Supersymmetric Standard Model, with branching fraction close to 100%

Synergies within the DK

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Collaboration experiment – theory• A. Hoang (University of Vienna)• Theory groups (Institute of High Energy Physics)

Development of algorithms (trigger, reconstruction, analysis)• R. Frühwirth (Institute of High Energy Physics, TU Vienna)• M. Jeitler (Institute of High Energy Physics, TU Vienna)

Experimental techniques, detector issues• M.Krammer (Institute of High Energy Physics, TU Vienna)

Added value

SUSY at the LHC SUSY at the LHC

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 C.-E. Wulz (Institute of High Energy Physics) 9

Thank you for your attention!

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