Abstract:
We study the associated production of a single top quark and a Higgs boson, in order to directly constrain the topHiggs coupling. Due to the destructive interference in the tchannel for standard model couplings, this process is very sensitive to both the magnitude and the sign of a nonstandard topHiggs coupling. We focus on the Higgs decay to two photons, that would be further enhanced in the scenario of a negative Yukawa coupling, and on the leptonic top decay channel.The analysis has an expected 95\% confidence level upper limit on the Higgs production cross section times $BR(H \to \gamma \gamma)$ of 4.1 times the expectation~(with $C_t = 1$). The expected significance of the analysis is 1.2 standard deviations. Zero events are observed in the signal region, leading to a 95\% upper limit of 4.1 times the expectation~(with $C_t = 1$).
