Neutral Higgs boson searches in the $H->\tau\tau->\mu\mu$ decay channel

This dissertation describes the search for Higgs bosons decaying to a pair of tau leptons both decaying to muons. The analysis was performed using events recorded by the CMS detector at the LHC in 2011 and 2012, at center-of-mass energy 7 TeV and 8 TeV respectively. The dataset corresponds to total integrated luminosity of 17 1/fb, 4.9 1/fb taken at 7 TeV center-of-mass energy and 12.1 1/fb at 8 TeV. The results were interpreted in the context of both the Standard Model and the Minimal Supersymmetric Standard Model. Upper limits were set to the Higgs production cross section in the former case and on the (tan(beta), mA) plane in the latter. The update of this analysis with more data, combined with other tau final states, lead to the first evidence of the Higgs coupling to leptons. Included in this document is also the study of the Z boson production followed by Z->tautau decay with two muons in the final state. This analysis was performed with 36 1/pb of data collected in 2010, at center-of-mass energy 7 TeV, by the CMS experiment. The result of this study was the measurement of the Z production cross section in proton-proton collisions. The analysis procedures developed for the Z boson decay to tau leptons were used to commission the Higgs boson searches in the same decay channel.