Search for resonant top quark plus jet production in t(t) over-bar + jets events with the ATLAS detector in pp collisions at √s=7 TeV

Abstract

This paper presents a search for a new heavy particle produced in association with a top or antitop quark. Two models in which the new heavy particle is a color singlet or a color triplet are considered, decaying, respectively, to t̅q or tq, leading to a resonance within the tt̅ +jets signature. The full 2011 ATLAS pp collision data set from the LHC (4.7 fb⁻¹) is used to search for tt̅ events produced in association with jets, in which one of the W bosons from the top quarks decays leptonically and the other decays hadronically. The data are consistent with the Standard Model expectation, and a new particle with mass below 430 Gev for both W′ boson and color triplet models is excluded at 95% confidence level, assuming unit right-handed coupling.