Search for Supersymmetry in Final States with a Single Lepton, B-Quark Jets, and Missing Transverse Energy at the CMS Experiment

Pietsch, Niklas

Dissertation / PhD Thesis

PUBDB-2014-03943

Search for Supersymmetry in Final States with a Single Lepton, B-Quark Jets, and Missing Transverse Energy at the CMS Experiment

Pietsch, N. (Corresponding Author)DESY*

2014
Hamburg

Hamburg 231 pp. (2014) [10.3204/PUBDB-2014-03943] = Dissertation, University of Hamburg, 2014

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Please use a persistent id in citations: doi:10.3204/PUBDB-2014-03943

Report No.: DESY-THESIS-2014-032

Abstract: Supersymmetry constitutes an attractive extension of the Standard Model of parti- cle physics. It provides a natural Dark Matter candidate and is able to resolve the hierarchy problem. If Supersymmetry is a natural solution of the hierarchy problem, the supersymmetric partner particles of the top and the bottom quark may be copi- ously produced in proton-proton collisions at the Large Hadron Collider, resulting in nal states with isolated leptons, jets, some of which originate from a bottom quark, and missing transverse energy. In this thesis, the rst search for Supersymmetry in events with a single lepton, bottom quark-jets, and missing transverse energy at the Compact Muon Solenoid ex- periment is presented. This search is one of the worldwide rst analyses that directly probe natural Supersymmetry. The search is performed with proton-proton collision data recorded at a center-of-mass energy of 7 TeV during 2011, corresponding to an integrated luminosity of 4 : 98 fb-1 To minimize the systematic uncertainties of the measurement, the expected background from Standard Model processes is modeled with a data-driven method. No signicant deviation from the Standard Model pre- diction is observed. Therefore, the results are interpreted as exclusion limits upon the parameters of the Constrained Minimal Supersymmetric Standard Model and a simplied model with four top quarks in the nal state. In preparation of the next data-taking periods, where proton-proton collisions at envisaged center-of-mass en- ergies of 13 and 14 TeV will open up new kinematic regions with a large discovery potential for physics beyond the Standard Model, prospects of measuring dijet-mass endpoints resulting from gluino decays are investigated.

Keyword(s): Dissertation

Note: Dissertation, University of Hamburg, 2014

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