Topical seminar: Search for Lepton Flavour Violating Higgs decays in CMS

by Dr Maria Cepeda Hermida (CERN)

Monday 12 Oct 2015, 10:00 → 11:00 Europe/Brussels

Jean Sacton Seminar room (1G003) (IIHE, VUB)

abstract: The discovery of the Higgs Boson at a mass of 125 GeV has started a new era in particle physics, in which establishing its compatibility with the Standard Model is key. In this seminar I will present the first direct search for lepton violating decays of the Higgs boson, as performed by the CMS experiment of the LHC, to muon-tau, electron-tau and muon-electron pairs. These exotic decays arise naturally in beyond the Standard Model scenarios such as those with more than one Higgs doublet, composite Higgs models, Randall-Sundrum models, and many others. The data sample used corresponds to an integrated luminosity of 19.7 fb-1 collected in pp collisions at 8 TeV. The sensitivity of the search is an order of magnitude better than the existing indirect limits for the muon-tau and electron-tau channels, and a slight excess of data with a significance of 2.5 sigma is observed in the muon-tau channel. The results allow to set limits at 95% CL on the branching ratio of h->mu tau to < 1.51%, of h->e tau to 0.70%, and of h->emu to 0.036%. These are then used to constrain the Y(ll') Yukawa couplings.

Slides BrusselsSeminar.pdf