A search for lepton-flavor-violating decays of the $Z$ boson into a $\tau$-lepton and a light lepton with the ATLAS detector

• Autor(a) principal: ATLAS collaboration (2920 authors)
• Data de Publicação: 2018
• Outros Autores: Aguilar Saavedra, Juan Antonio, Amor Dos Santos, Susana Patricia, Araque Espinosa, Juan Pedro, Castro, Nuno Filipe, Conde Muino, Patricia, Da Cunha Sargedas De Sousa, Mario Jose, Dias DO Vale, Tiago, Faisca Rodrigues Pereira, Rui Miguel, Fiolhais, Miguel, Galhardo, Bruno, Gomes, Agostinho, Goncalo, Ricardo, Jorge, Pedro, Machado Miguens, Joana, Maio, Amelia, Maneira, Jose, Mendes Gouveia, Emanuel Demetrio, Oleiro Seabra, Luis Filipe, Onofre, Antonio, Costa Batalha Pedro, Rute, Pereira Peixoto, Ana Paula, Santos, Helena, Saraiva, Joao, Silva, Jose Manuel, Tavares Delgado, Ademar, Veloso, Filipe, Wolters, Helmut
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.26/27622

Direct searches for lepton flavor violation in decays of the Z boson with the ATLAS detector at the LHC are presented. Decays of the Z boson into an electron or muon and a hadronically decaying τ lepton are considered. The searches are based on a data sample of proton-proton collisions collected by the ATLAS detector in 2015 and 2016, corresponding to an integrated luminosity of 36.1  fb-1 at a center-of-mass energy of s=13  TeV. No statistically significant excess of events above the expected background is observed, and upper limits on the branching ratios of lepton-flavor-violating decays are set at the 95% confidence level: B(Z→eτ)<5.8×10-5 and B(Z→μτ)<2.4×10-5. This is the first limit on B(Z→eτ) with ATLAS data. The upper limit on B(Z→μτ) is combined with a previous ATLAS result based on 20.3  fb-1 of proton-proton collision data at a center-of-mass energy of s=8  TeV and the combined upper limit at 95% confidence level is B(Z→μτ)<1.3×10-5.