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

Abstract: 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.