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Searching for the charged Higgs boson in the tau nu analysis using Boosted Decision Trees

his thesis implements a multivariate analysis in the current cut- based search for the charged Higgs bosons, which are new scalar particles predicted by several extensions to the Standard Model. Heavy charged Higgs bosons (mH± mtop) produced in association with a top quark de- caying via H± → τν are considered. The final state contains a hadronic τ decay, missing transverse energy and a hadronically decaying top quark. This study is based on Monte Carlo samples simulated at CM-energy √ s = 13 TeV for signal and backgrounds. The figure of merit to measure the improvement of the new method with respect to the old analysis is the separation between the signal and background distributions. Four mass points (mH± = 200, 400, 600, 1000 GeV) are considered, and an increase of the separation ranging from 2.6% (1000 GeV) to 29.2% (200 GeV) com- pared to the current cut-based analysis is found. / Denna studie implementerar en flervariabel-analys till den befintliga snitt-baserade analysen av laddade Higgs-bosoner, nya skal ̈arpartiklar fo ̈rutsagda av flertalet fo ̈rl ̈angningar av Standardmodellen. Studien antar tunga lad- dade Higgs-bosoner (mH± mtop) producerade tillsammans med en top- kvark som fo ̈rfaller via H± → τν. Sluttillst ̊andet best ̊ar av ett hadroniskt τ-so ̈nderfall, f ̈orlorad transversell energi och en hadroniskt so ̈nderfallande √ toppkvark. Studien a ̈r baserad p ̊a data f ̈or signal och bakgrund. Fo ̈r att ma ̈ta fo ̈rba ̈ttringen av analysens ka ̈nslighet anva ̈nds avst ̊and mellan bakgrundens och signalens distribu- tioner som godhetstal. Fyra masspunkter (mH± = 200, 400, 600, 1000 GeV) anva ̈nds, och en o ̈kning av avst ̊and fr ̊an 2.6% (1000 GeV) till 29.2% (200 GeV) hittades.

Identiferoai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-301351
Date January 2016
CreatorsHallberg, Jesper
PublisherUppsala universitet, Högenergifysik
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeStudent thesis, info:eu-repo/semantics/bachelorThesis, text
Formatapplication/pdf
Rightsinfo:eu-repo/semantics/openAccess
RelationFYSAST ; FYSMAS1045

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