Expected limits on the cross section of additional neutral Higgs bosons $ϕ$ $→$ $τ τ$ with CMS Run 3 data

Additional neutral Higgs bosons are predicted in several extensions of the Standard model.This thesis presents the expected upper limits on the production cross section times branchingratio of additional neutral Higgs bosons produced via gluon-gluon fusion and decayinginto a pair of τ leptons, derived from CMS Run 3 data. The masses of the neutral Higgsboson probed in this study range from 70 GeV to 1.2TeV. This analysis is carried out using34.75 fb−1 of proton-proton collision data from 2022 recorded at a center-of-mass energy of13.6TeV. A cut-based event selection strategy is used to suppress Standard Model backgroundcontributions and extract a signal from a narrow spin-0 resonance in the e±μ∓ finalstate. Expected limits at the 95% confidence level (CL) are inferred via a binned profilelikelihood fit. The median expected upper limits at the 95% CL range from O(10 pb) for amass of 70 GeV to O(0.1 pb) for a mass of 1.2TeV.