TY  - THES
AU  - Meyer, Mareike
TI  - Search for Leptoquarks and Dark Matter in final states with top quarks at the CMS experiment
IS  - DESY-THESIS-2017-032
PB  - Universität Hamburg
VL  - Dr.
CY  - Hamburg
M1  - PUBDB-2017-08544
M1  - DESY-THESIS-2017-032
T2  - DESY-THESIS
SP  - 257
PY  - 2017
N1  - Universität Hamburg, Diss., 2017
AB  - This thesis presents two searches for physics beyond the Standard Model (SM). A searchfor pair production of third-generation leptoquarks decaying into a top quark and a taulepton using pp collision data recorded at a center-of-mass energy of 8TeV with theCMS experiment is presented. The search is based on an event selection requiring anisolated muon or electron candidate, one hadronically decaying tau lepton candidate andat least three jets. The main reducible background originates from processes, where ajet is misidentied as a tau lepton candidate. A measurement of the tau lepton misidentication rate is performed in a sideband enriched in W + jets events. The transversemomentum distribution of the leading tau lepton candidate is used for the statisticalinterpretation of the result. No excess over the SM expectation is observed. Uppercross section limits on the pair production cross section of leptoquarks decaying into atop quark and a tau lepton are set. By combining the presented search with an analysisrequiring same-sign muon-tau lepton-pairs, leptoquarks with masses below 685 GeV(695 GeV expected) are excluded at 95
LB  - PUB:(DE-HGF)3 ; PUB:(DE-HGF)29 ; PUB:(DE-HGF)11
DO  - DOI:10.3204/PUBDB-2017-08544
UR  - https://bib-pubdb1.desy.de/record/332278
ER  -