Search for direct pair production of supersymmetric partners to the τ lepton in proton–proton collisions at √s=13TeV

Abstract

A search is presented for $${\uptau }_{}^{}$$ τ slepton pairs produced in proton–proton collisions at a center-of-mass energy of 13$$\,\text {TeV}$$ TeV . The search is carried out in events containing two $${\uptau }_{}^{}$$ τ leptons in the final state, on the assumption that each $${\uptau }_{}^{}$$ τ slepton decays primarily to a $${\uptau }_{}^{}$$ τ lepton and a neutralino. Events are considered in which each $${\uptau }_{}^{}$$ τ lepton decays to one or more hadrons and a neutrino, or in which one of the $${\uptau }_{}^{}$$ τ leptons decays instead to an electron or a muon and two neutrinos. The data, collected with the CMS detector in 2016 and 2017, correspond to an integrated luminosity of 77.2$$\,\text {fb}^{-1}$$ 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 $${\uptau }_{}^{}$$ τ slepton pair production in various models for $${\uptau }_{}^{}$$ τ slepton masses between 90 and 200$$\,\text {GeV}$$ GeV and neutralino masses of 1, 10, and 20$$\,\text {GeV}$$ GeV . In the case of purely left-handed $${\uptau }_{}^{}$$ τ slepton production and decay to a $${\uptau }_{}^{}$$ τ lepton and a neutralino with a mass of 1$$\,\text {GeV}$$ GeV , the strongest limit is obtained for a $${\uptau }_{}^{}$$ τ slepton mass of 125$$\,\text {GeV}$$ GeV at a factor of 1.14 larger than the theoretical cross section.