Search for a light charged Higgs boson in the decay channel H → cs̄ in tt̄ events using pp collisions at √s = 7 TeV with the ATLAS detector. European Physical Journal C Volume 73, Issue 6, June 2013, Pages 1-20

A search for a charged Higgs boson (H ) in tt̄ decays is presented, where one of the top quarks decays via t→H b, followed by H → two jets (cs̄). The other top quark decays to Wb, where the W boson then decays into a lepton (e/μ) and a neutrino. The data were recorded in pp collisions at √s = 7 TeV by the ATLAS detector at the LHC in 2011, and correspond to an integrated luminosity of 4.7 fb-1. With no observation of a signal, 95 % confidence level (CL) upper limits are set on the decay branching ratio of top quarks to charged Higgs bosons varying between 5 % and 1 % for H masses between 90 GeV and 150 GeV, assuming B(H → cs̄ = 100 %.