Search for resonances in the mass spectrum of muon pairs produced in association with b quark jets in proton-proton collisions at √s = 8 and 13 TeV

Abstract

A search for resonances in the mass range 12{70 GeV produced in association with a b quark jet and a second jet, and decaying to a muon pair, is reported. The analysis is based on data from proton-proton collisions at center-of-mass energies of 8 and 13TeV, collected with the CMS detector at the LHC and corresponding to integrated luminosities of 19.7 and 35.9 fbð€€€1, respectively. The search is carried out in two mutually exclusive event categories. Events in the rst category are required to have a b quark jet in the central region ( 2:4) and at least one jet in the forward region ( > 2:4). Events in the second category are required to have two jets in the central region, at least one of which is identi ed as a b quark jet, no jets in the forward region, and low missing transverse momentum. An excess of events above the background near a dimuon mass of 28 GeV is observed in the 8TeV data, corresponding to local signi cances of 4.2 and 2.9 standard deviations for the rst and second event categories, respectively. A similar analysis conducted with the 13TeV data results in a mild excess over the background in the rst event category corresponding to a local signi cance of 2.0 standard deviations, while the second category results in a 1.4 standard deviation de cit. The ducial cross section measurements and 95% con dence level upper limits on those for a resonance consistent with the 8TeV excess are provided at both collision energies.