Search for an excited quark decaying in semi-leptonic channel

A search is performed for a pair-produced excited top quark, t , that decays to a top quark and a gluon using data collected by the CMS detector from pp collisions at p s = 8 TeV. The search is performed using events that have a single isolated muon or electron, missing transverse momentum, and at least six jets, one of which must be identified as originating from the fragmentation of a b quark. The data analyzed correspond to an integrated luminosity of 19.6 fb 1 . No significant excess is observed and we set a lower limit on the t -quark mass of 790 GeV = c 2 at 95% confidence level.