The first direct search for lepton-flavour-violating decays of the recently discovered Higgs boson (H) is described. The search is performed in the H →μτeand H →μτhchannels, where τeand τhare tau leptons reconstructed in the electronic and hadronic decay channels, respectively. The data sample used in this search was collected in pp collisions at a centre-of-mass energy of √s=8TeVwith the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 19.7fb−1. The sensitivity of the search is an order of magnitude better than the existing indirect limits. A slight excess of signal events with a significance of 2.4 standard deviations is observed. The p-value of this excess at MH=125GeVis 0.010. The best fit branching fraction is B(H →μτ) =(0.84+0.39−0.37)%. A constraint on the branching fraction, B(H →μτ) <1.51%at 95% confidence level is set. This limit is subsequently used to constrain the μ–τYukawa couplings to be less than 3.6 ×10−3.

Search for lepton-flavour-violating decays of the Higgs boson

Sola, V.;AMAPANE, Nicola Carlo;ARGIRO', Stefano;BELLAN, Riccardo;COSTA, Marco;COVARELLI, Roberto;MIGLIORE, Ernesto;MONACO, Vincenzo;OBERTINO, Maria Margherita;ROMERO, Alessandra;SACCHI, Roberto;SOLANO, Ada Maria;
2015-01-01

Abstract

The first direct search for lepton-flavour-violating decays of the recently discovered Higgs boson (H) is described. The search is performed in the H →μτeand H →μτhchannels, where τeand τhare tau leptons reconstructed in the electronic and hadronic decay channels, respectively. The data sample used in this search was collected in pp collisions at a centre-of-mass energy of √s=8TeVwith the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 19.7fb−1. The sensitivity of the search is an order of magnitude better than the existing indirect limits. A slight excess of signal events with a significance of 2.4 standard deviations is observed. The p-value of this excess at MH=125GeVis 0.010. The best fit branching fraction is B(H →μτ) =(0.84+0.39−0.37)%. A constraint on the branching fraction, B(H →μτ) <1.51%at 95% confidence level is set. This limit is subsequently used to constrain the μ–τYukawa couplings to be less than 3.6 ×10−3.
2015
749
337
362
http://www.sciencedirect.com/science/journal/03702693
CMS; Higgs; Lepton-flavour-violation; Muons; Physics; Taus; Nuclear and High Energy Physics
Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V.M.; Hartl, C.; Hör...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1577988
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