Search for W' → tb decays in the lepton + jets final state in pp collisions at = 8 TeV

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 = 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 , μ), 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') > 2 .05 TeV. For W^' bosons with purely left-handed couplings, including interference effects, the observed 95% confidence level limit is M(W') > 1 .84 TeV. The results presented in this paper are the most stringent limits published to date. [Figure not available: see fulltext.]