Search for lepton-flavour-violating decays of the Higgs boson
BMWFW (Austria) ; FWF (Austria) ; FNRS (Belgium) ; FWO (Belgium) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; MES (Bulgaria) ; CERN ; CAS (China) ; MoST (China) ; NSFC (China) ; COLCIENCIAS (Colombia) ; MSES (Croatia) ; CSF (Croatia) ; RPF (Cyprus) ; MoER (Estonia) ; ERC IUT (Estonia) ; ERDF (Estonia) ; Academy of Finland (Finland) ; MEC (Finland) ; HIP (Finland) ; CEA (France) ; CNRS/IN2P3 (France) ; BMBF (Germany) ; DFG (Germany) ; HGF (Germany) ; GSRT (Greece) ; OTKA (Hungary) ; NIH (Hungary) ; DAE (India) ; DST (India) ; IPM (Iran) ; SFI (Ireland) ; INFN (Italy) ; MSIP (Republic of Korea) ; NRF (Republic of Korea) ; LAS (Lithuania) ; MOE (Malaysia) ; UM (Malaysia) ; CINVESTAV (Mexico) ; CONACYT (Mexico) ; SEP (Mexico) ; UASLP-FAI (Mexico) ; MBIE (New Zealand) ; PAEC (Pakistan) ; MSHE (Poland) ; NSC (Poland) ; FCT (Portugal) ; JINR (Dubna) ; MON (Russia) ; RosAtom (Russia) ; RAS (Russia) ; RFBR (Russia) ; MESTD (Serbia) ; SEIDI (Spain) ; CPAN (Spain) ; Swiss Funding Agencies (Switzerland) ; MST (Taipei) ; ThEPCenter (Thailand) ; IPST (Thailand) ; STAR (Thailand) ; NSTDA (Thailand) ; TUBITAK (Turkey) ; TAEK (Turkey) ; NASU (Ukraine) ; SFFR (Ukraine) ; STFC (United Kingdom) ; DOE (USA) ; NSF (USA) ; Marie-Curie programme ; European Research Council ; EPLANET (European Union) ; Leventis Foundation ; A.P. Sloan Foundation ; Alexander von Humboldt Foundation ; Belgian Federal Science Policy Office ; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium) ; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium) ; Ministry of Education, Youth and Sports (MEYS) of the Czech Republic ; Council of Science and Industrial Research, India ; HOMING PLUS programme of Foundation for Polish Science ; European Union, Regional Development Fund ; Consorzio per la Fisica (Trieste) ; MIUR project (Italy) ; EU-ESF ; Greek NSRF ; National Priorities Research Program by Qatar National Research Fund ; Compagnia di San Paolo (Torino) ; Science and Technology Facilities Council ; MIUR project (Italy): 20108T4XTM ; Science and Technology Facilities Council: ST/L005603/1 ; Science and Technology Facilities Council: ST/K003542/1 ; Science and Technology Facilities Council: ST/M005356/1 ; Science and Technology Facilities Council: ST/J004901/1 ; Science and Technology Facilities Council: ST/J005665/1 ; Science and Technology Facilities Council: ST/I005912/1 ; Science and Technology Facilities Council: ST/L00609X/1 ; Science and Technology Facilities Council: ST/M004775/1 ; Science and Technology Facilities Council: ST/L00609X/1 GRIDPP ; Science and Technology Facilities Council: ST/K001256/1 ; Science and Technology Facilities Council: ST/M005356/1 GRIDPP ; Science and Technology Facilities Council: ST/K003844/1 GRIDPP ; Science and Technology Facilities Council: ST/K003844/1 ; Science and Technology Facilities Council: GRIDPP ; Science and Technology Facilities Council: ST/J50094X/1 ; Science and Technology Facilities Council: ST/I505580/1 ; Science and Technology Facilities Council: ST/N000250/1 ; Science and Technology Facilities Council: ST/K001604/1 ; Science and Technology Facilities Council: ST/I005912/1 GRIDPP ; Science and Technology Facilities Council: ST/K001639/1 ; Science and Technology Facilities Council: CMS ; 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 -> mu tau(e) and H -> mu tau(h) channels, where tau(e) and tau(h) are 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 root s = 8 TeV with the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 19.7 fb(-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 M-H = 125 GeV is 0.010. The best fit branching fraction is beta(H -> mu tau) = (0.84(-0.37)(+0.39))%. A constraint on the branching fraction, beta(H -> mu tau) < 1.51% at 95% confidence level is set. This limit is subsequently used to constrain the mu-tau Yukawa couplings to be less than 3.6 x 10(-3). (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.