Searches for Z' and Higgs Bosons Decaying into Hadronic Tau Pairs at CMS/LHC

byNil VallsAn elegant solution to the mystery of electroweak symmetry breaking and theorigin of mass was proposed in the 1960s, yet it has taken several generations ofparticle accelerators and detectors to discover the first strong candidate for the socalled Higgs boson, which is implied by the theory. A positive identification wouldcomplete the Standard Model (SM), the most successful description of elementaryparticles and interactions to date. Searches for the SM Higgs boson production inassociation with top-quark pairs will provide additional information on the likely SMHiggs boson detection by the ATLAS and CMS experiments at the LHC in 2012, aswell as the only means of directly measuring its coupling to top quarks. The firstCMS search for the SM Higgs boson decaying into hadronic tau pairs in association√with top-quark pairs is presented in this dissertation: with 19.4 fb−1 of s = 8 TeVp–p collision data collected by the CMS experiment, the expected and observed upper+−¯limits on the product of the cross section and branching ratio for the tt H → τh τh