The signatures of the new particles $h_2$ and $Z_{\mu \tau }$ at e-p colliders in the $U(1{)}_{L_{\mu }-L_{\tau }}$ model

Abstract

Considering the superior performances of the future e-p colliders, LHeC and FCC-eh, we discuss the feasibility of detecting the extra neutral scalar $h_2$ and the light gauge boson $Z_{\mu \tau }^{}$, which are predicted by the ${U(1)}_{L_{\mu }^{}-L_{\tau }^{}}$ model. Taking into account the experimental constraints on the relevant free parameters, we consider all possible production channels of $h_2$ and $Z_{\mu \tau }^{}$ at e-p colliders and further investigate their observability through the optimal channels in the case of the beam polarization P($e^{-}$)= -0.8. We find that the signal significance above 5$\sigma$ of $h_2$ as well as $Z_{\mu \tau }^{}$ detecting can be achieved via $e^{-}p\to e^{-}j{h}_2(\to Z_{\mu \tau }{Z}_{\mu \tau })\to e^{-}j+/E_T^{}$ process and a 5$\sigma$ sensitivity of $Z_{\mu \tau }^{}$ detecting can be gained via $e^{-}p\to e^{-}j{h}_1(\to Z_{\mu \tau }^{}{Z}_{\mu \tau }^{})\to e^{-}j+/E_T^{}$ process at e-p colliders with appropriate parameter values and a designed integrated luminosity. However, the signals of $h_2$ decays into pair of SM particles are difficult to be detected.

Comments: 22 pages, 9 figures, references added and typos are corrected