After the finding of a Higgs boson at the Large Hadron Collider of CERN, the next milestone in experimental particle physics is the detection of a new particle beyond the Standard Model. Many of the popular extensions of the Standard Model are so called Two-Higgs-doublet models, that include five physical Higgs bosons in total. Two of the bosons are neutral scalars, two are charged scalars and one is a pseudoscalar.
The first part of this thesis presents the Standard Model of particle physics as a gauge field theory where the gauge principle is used to introduce interactions between the particles. Quantum electrodynamics, weak interactions and quantum chromodynamics with their properties are discussed. The electroweak symmetry breaking through the Higgs mechanism and its implications for the masses of the particles are shown. The considerations on the Standard Model are concluded by discussing some of the problems in the Standard Model.
Supersymmetric extensions to the Standard Model are introduced, motivated by their potential to solve some of the problems and by the framework for new physics the supersymmetry provides. The Higgs sector in the more constrained minimal supersymmetry scenario is discussed and some of the properties for these new Higgs bosons are given.
The latter part of the thesis focuses on the experimental aspects of high energy particle physics. The search for the charged Higgs boson in the H+ → τ+ ντ decay channel, with the tau lepton decaying into hadronic decay products is presented in detail. Vetoing collision events with more than one tau particle is shown to enhance the transverse mass resolution of the analysis, improving the signal detection. Methods for performing a tau veto are discussed and the problems in performing the tau veto are studied using 13 TeV collision event simulations and data from 2015 from the CMS detector at the LHC. No viable way of performing the tau veto in such a way that it improves the overall analysis is found.
