Search for W - GT tb decays in the lepton plus jets final state in pp collisions at root s=8 TeV

Abstract

Results are presented from a search for the production of a heavy gauge boson W decaying into a top and a bottom quark, using a data set collected by the CMS experiment at root s = 8 TeV and corresponding to an integrated luminosity of 19.5 fb(-1). Various models of W-boson production are studied by allowing for an arbitrary combination of left-and right-handed couplings. The analysis is based on the detection of events with a lepton (e, mu), jets, and missing transverse energy in the final state. No evidence for W-boson production is found and 95% confidence level upper limits on the production cross section times branching fraction are obtained. For W bosons with purely right-handed couplings, and for those with left-handed couplings assuming no interference effects, the observed 95% confidence level limit is M(W) GT 2.05TeV. For W bosons with purely left-handed couplings, including interference effects, the observed 95% confidence level limit is M(W) GT 1.84 TeV. The results presented in this paper are the most stringent limits published to date.