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 ffiffiffis p ¼ 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: BðZ → eτÞ < 5.8 × 10−5 and BðZ → μτÞ < 2.4 × 10−5. This is the first limit on BðZ → eτÞ with ATLAS data. The upper limit on BðZ → μτÞ 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 ffiffiffis p ¼ 8 TeV and the combined upper limit at 95% confidence level is BðZ → μτÞ < 1.3 × 10−5.
Aaboud M., A.G. (2018). Search for lepton-flavor-violating decays of the Z boson into a τ lepton and a light lepton with the ATLAS detector. PHYSICAL REVIEW D, 98(9), 092010-1-092010-31 [10.1103/PhysRevD.98.092010].
Search for lepton-flavor-violating decays of the Z boson into a τ lepton and a light lepton with the ATLAS detector
Alberghi G. L.;Bellagamba L.;Bindi M.;Boscherini D.;Cabras G.;Caforio D.;De Castro S.;Di Sipio R.;Fabbri L.;Franchini M.;Gabrielli A.;Gabrielli A.;Giacobbe B.;Lasagni Manghi F.;Macchiolo A.;Massa L.;Mengarelli A.;Monzani S.;Polini A.;Rinaldi L.;Romano M.;Sbarra C.;Sbrizzi A.;Semprini-Cesari N.;Talyshev A. A.;Todome K.;Ucchielli G.;Valentinetti S.;Villa M.;Vittori C.;Zobernig G.;Zoccoli A.;
2018
Abstract
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 ffiffiffis p ¼ 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: BðZ → eτÞ < 5.8 × 10−5 and BðZ → μτÞ < 2.4 × 10−5. This is the first limit on BðZ → eτÞ with ATLAS data. The upper limit on BðZ → μτÞ 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 ffiffiffis p ¼ 8 TeV and the combined upper limit at 95% confidence level is BðZ → μτÞ < 1.3 × 10−5.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
