Search for resonant top plus jet production in ttbar + jets events with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper searches for new heavy particles produced with top quarks in ttbar + jets events at 7 TeV, setting mass exclusion limits and testing models beyond the Standard Model using ATLAS data.

Contribution

It introduces a search for resonant top plus jet production in ttbar + jets events, considering color singlet and triplet models, and sets new mass exclusion limits based on ATLAS data.

Findings

No significant excess found over Standard Model predictions.

Excluded new particles below 430 GeV mass at 95% confidence level.

Provided constraints on models with heavy particles decaying to top and jet.

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 tbarq or tq, leading to a resonance within the ttbar + jets signature. The full 2011 ATLAS pp collision dataset from the LHC (4.7 fb-1) is used to search for ttbar 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.