Searches for lepton-flavour-violating decays of the Higgs boson in $\sqrt{s}=13$ TeV pp collisions with the ATLAS detector

• Main Authors: Aguilar Saavedra, Juan Antonio, Alimonti, Gianluca, Andari, Nansi, Barkeloo, Jason Tylor Colt, Barnett, Bruce, Blenessy, Zuzana, Bartos, Pavol, Belotskiy, Konstantin, Bertella, Claudia, Bittrich, Carsten, Bokan, Petar, Bold, Tomasz, Burghgrave, Blake, Butler, John, Buzatu, Adrian, Calvetti, Milene, Cardarelli, Roberto, Carra, Sonia, Cerri, Alessandro, Chan, Wai Yuen, Chen, Ye, Cherkaoui El Moursli, Rajaa, Chiodini, Gabriele, Clark, Philip James, Constantinescu, Serban, Costa, Maria Jose, Dang, Nguyen Phuong, Dawson, Ian, De Salvo, Alessandro, Della Pietra, Massimo, Delporte, Charles, Di Valentino, David, Díez Cornell, Sergio, Dolezal, Zdenek, Donini, Julien, Duan, Yanyun, Evans, Hal, Fiorini, Luca, Fomin, Nikolai, Ghasemi, Sara, Gouighri, Mohamed, Grimm, Kathryn, Guan, Liang, Havener, Laura Brittany, Horii, Yasuyuki, Horyn, Lesya Anna, Hoummada, Abdeslam, Hyrych, Sofiia, Jinaru, Adam, Junggeburth, Johannes Josef, Kato, Chikuma, Klein, Max, Kourkoumelis, Christine, Leggett, Charles, Leight, William Axel, Levinson, Lorne, Lo, Cheuk Yee, Lutz, Margaret Susan, Madaffari, Daniele, Makovec, Nikola, Martin, Victoria Jane, Mikuz, Marko, Milesi, Marco, Miyagawa, Paul, Moenig, Klaus, Neep, Thomas James, Olszowska, Jolanta, Pagan Griso, Simone, Parker, Andy, Sotto-Maior Peralva, Bernardo, Petrov, Mariyan, Peyaud, Alan, Puzo, Patrick, Rashid, Tasneem, Rozanov, Alexander, Saimpert, Matthias, Salvatore, Pasquale Fabrizio, Schroeder, Frederic, Sciandra, Andrea, Shatalov, Pavel, Sijacki, Djordje, Stucci, Stefania Antonia, Thais, Savannah Jennifer, Trefzger, Thomas, Trocme, Benjamin, Tsukerman, Ilya, Valdes Santurio, Eduardo, Valentinetti, Sara, Valero, Alberto, Vanadia, Marco, Virdee, Govindraj Singh, Wagner, Wolfgang, Wang, Wei, Winston, Oliver James, Yamazaki, Tomohiro, Yue, Xiaoguang, Zaitsev, Alexander, Zeissner, Sonja Verena, Zobernig, Georg, Zoch, Knut
• Format: Report
• Language: English
• Subjects: background; branching ratio: upper limit; CERN LHC Coll; experimental results; GeV-cms; Higgs particle > > electron tau; Higgs particle > > muon tau; Higgs particle: branching ratio; Higgs particle: leptonic decay; Higgs particle: rare decay; lepton: flavor: violation; p p: colliding beams; p p: scattering
• ISSN: 1873-2445; 0370-2693
• DOI: 10.3204/pubdb-2019-05057

This Letter presents direct searches for lepton flavour violation in Higgs boson decays, $H\rightarrow e\tau$ and $H\rightarrow\mu\tau$, performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton-proton collisions at a centre-of-mass energy $\sqrt{s} = 13$ TeV, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits are 0.47% (0.34$^{+0.13}_{-0.10}$%) and 0.28% (0.37$^{+0.14}_{-0.10}$%) for $H\rightarrow e\tau$ and $H\rightarrow\mu\tau$, respectively.