Searches for neutral Higgs bosons in final states with two tau leptons using the CMS detector

The Compact Muon Solenoid (CMS) detector is a general-purpose detector located at the Large Hadron Collider at CERN. It was designed to test the predictions of the standard model and to search for the Higgs boson in addition to searches for new physics beyond the standard model. The analyses presented in this thesis are searches for neutral Higgs bosons with tau leptons in the final state. These searches use proton-proton collision data recorded by CMS during 2012, 2015 and 2016. The searches are performed in the context of the minimal supersymmetric standard model (MSSM). One of the analyses, using 19.7 fb$^{-1}$ of data collected during 2012 at √s = 8 TeV, is a search for a heavy neutral Higgs boson decaying into two 125 GeV Higgs bosons with standard model-like properties, with two b-quarks and two tau leptons in the final state. The other analyses use 2.3 fb$^{−1}$ of data collected during 2015 and 12.9 fb$^{−1}$ of data collected during 2016, both at √s = 13 TeV. These are searches for neutral MSSM Higgs bosons in the mass range of 90 GeV–3.2 TeV directly decaying into pairs of tau leptons. No significant excess is observed in any of the searches. Upper limits at the 95% confidence level are set on the cross section times branching ratio for the production of Higgs bosons in the MSSM. In addition, limits are set in the m$_{A}$-tanβ parameter space of several MSSM benchmark scenarios, and in the cos (β − α)-tan β parameter space of a two Higgs doublet model.