Search for a W' decaying into t and d quarks in p-p collisions at sqrt(s) = 7 TeV

A search is presented for a heavy W' decaying into top and down quarks. The new particle would be produced in association with a top quark, so events are selected based upon the semileptonic decay of a top-antitop quark pair, with the requirement of an additional jet. At least one of the jets in the event is required to be a b-quark jet. The data used comprise 5.0~fb$^{-1}$ of integrated luminosity and were recorded by the CMS detector in 2011 while the Large Hadron Collider was colliding protons at a center of mass energy $\sqrt{s}=$ 7~TeV. No significant excess above Standard Model expectation is observed, and, from a combination of the electron-plus-jets and muon-plus-jets channels, a lower limit is set on the W' mass of 839~GeV/c$^{2}$ at the 95\% confidence level.