Searches for the FCNC couplings from top-Higgs associated production signal with h → γγ at the LHC

In this paper, we study the observability of the top-Higgs flavor changing neutral current (FCNC) tqh coupling through the process pp→qg→t(→ℓ+bν)h(→γγ) at the Large Hadron Collider (LHC), where ℓ=e,μ. Our numerical results show that, in some parameter regions, the LHC may observe the above signals at the 5σ level. Otherwise, the branching ratios Br(t→uh) and Br(t→ch) can be respectively probed to 0.036% and 0.13% at 3σ level at 14 TeV LHC with the high integrated luminosity of 3000fb−1. On the other hand, studying the charge ratio for the lepton in top quark decay can be not only used to discriminate between signal and backgrounds, but also used to discriminate between tuh and tch couplings, for which anomalous single top production comes from the up initiated channel and charm initiated channel.