Search for direct pair production of supersymmetric partners to the τ lepton in proton–proton collisions at √s=13TeV
CMS Collaboration, Albert M. Sirunyan, Malte Backhaus, Pirmin Berger, Nadezda Chernyavskaya, Günther Dissertori, Michael Dittmar, Mauro Donegà, Christian Dorfer, Tirso Alejandro Gomez Espinosa, Christophorus Grab, Dmitry Hits
(+24 others)
2020
A search is presented for τ slepton pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. The search is carried out in events containing two τ leptons in the final state, on the assumption that each τ slepton decays primarily to a τ lepton and a neutralino. Events are considered in which each τ lepton decays to one or more hadrons and a neutrino, or in which one of the τ leptons decays instead to an electron or a muon and two neutrinos. The data, collected with the
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... detector in 2016 and 2017, correspond to an integrated luminosity of 77.2 fb −1 . The observed data are consistent with the standard model background expectation. The results are used to set 95% confidence level upper limits on the cross section for τ slepton pair production in various models for τ slepton masses between 90 and 200 GeV and neutralino masses of 1, 10, and 20 GeV. In the case of purely left-handed τ slepton production and decay to a τ lepton and a neutralino with a mass of 1 GeV, the strongest limit is obtained for a τ slepton mass of 125 GeV at a factor of 1.14 larger than the theoretical cross section. Event reconstruction and simulation The event reconstruction uses a particle-flow (PF) algorithm [40] that combines information from the tracker, calorimeter, and muon systems to identify charged and neutral hadrons, photons, electrons, and muons in an event. The missing transverse momentum vector, p miss T , is computed as the negative of the vector sum of the p T of all PF candidates reconstructed in an event, and its magnitude p miss T is used in the search as a discriminator between signal and SM background. Events selected for the search are required to pass filters [41] designed to remove detector-and beam-related backgrounds, and must have at least one reconstructed vertex. Usually, more than one such vertex is reconstructed because of pileup, i.e., multiple proton-proton (pp) collisions within the same or neighboring bunch crossings. The mean num-123 189
doi:10.3929/ethz-b-000404946
fatcat:7ig64vkugnhkxm3ywdku2h5asi
