Searches for the Anomalous FCNC Top-Higgs Couplings with Polarized Electron Beam at the LHeC

Abstract

In this paper, we study the single top and Higgs associated production ${\mathrm{e}}^{-}\mathrm{p}\to {\nu }_{\mathrm{e}}\bar{\mathrm{t}}\to {\nu }_{\mathrm{e}}\mathrm{h}\bar{\mathrm{q}}(\mathrm{h}\to \mathrm{b}\bar{\mathrm{b}})$ in the top-Higgs FCNC couplings at the LHeC with the electron beam energy of $E_e$ = 60 GeV and $E_e$ = 120 GeV, combination of a 7 TeV and 50 TeV proton beam. With the possibility of e-beam polarization ($p_e$ = 0, $\pm 0.6$), we distinct the Cut-based method and the Multivariate Analysis (MVA) based method, and compare with the current experimental and theoretical limits. It is shown that the branching ratio Br $(\mathrm{t}\to \mathrm{uh})$ can be probed to 0.113 (0.093) $\%$, 0.071 (0.057) $\%$, 0.030 (0.022) $\%$ and 0.024 (0.019) $\%$ with the Cut-based (MVA-based) analysis at ($E_p$, $E_e$) = (7 TeV, 60 GeV), ($E_p$, $E_e$) = (7 TeV, 120 GeV), ($E_p$, $E_e$) = (50 TeV, 60 GeV) and ($E_p$, $E_e$) = (50 TeV, 120 GeV) beam energy and 1$\sigma$ level. With the possibility of e-beam polarization, the expected limits can be probed down to 0.090 (0.073) $\%$, 0.056 (0.045) $\%$, 0.024 (0.018) $\%$ and 0.019 (0.015) $\%$, respectively.

Comments: 13pages, 5 figures. Advance in High Energy Physics