Searches for additional Higgs bosons and for vector leptoquarks in tt final states in proton-proton collisions at √s = 13 TeV

Abstract

Three searches are presented for signatures of physics beyond the standard model (SM) in ττ final states in proton-proton collisions at the LHC, using a data sample collected with the CMS detector at √s = 13TeV, corresponding to an integrated luminosity of 138 fb−¹. Upper limits at 95% confidence level (CL) are set on the products of the branching fraction for the decay into T leptons and the cross sections for the production of a new boson ɸ, in addition to the H(125) boson, via gluon fusion (ggɸ) or in association with b quarks, ranging from O(10 pb) for a mass of 60 GeV to 0.3 fb for a mass of 3.5TeV each. The data reveal two excesses for ggɸ production with local p-values equivalent to about three standard deviations at mɸ = 0.1 and 1.2TeV. In a search for t-channel exchange of a vector leptoquark U₁, 95% CL upper limits are set on the dimensionless U₁ leptoquark coupling to quarks and τ leptons ranging from 1 for a mass of 1TeV to 6 for a mass of 5TeV, depending on the scenario. In the interpretations of the M¹²⁵h and M¹²⁵h,EFT minimal supersymmetric SM benchmark scenarios, additional Higgs bosons with masses below 350 GeV are excluded at 95% CL.