Resonant leptogenesis in minimal $U(1{)}_X$ extensions of the Standard Model

Abstract

We investigate a general $U(1{)}_X$ scenario where we introduce three generations of Standard Model (SM) singlet Right Handed Neutrinos (RHNs) to generate the light neutrino mass through the seesaw mechanism after the breaking of $U(1{)}_X$ and electroweak symmetries. In addition to that, a general $U(1{)}_X$ scenario involves an SM-singlet scalar field and due to the $U(1{)}_X$ symmetry breaking the mass of a neutral beyond the SM (BSM) gauge boson $Z^{\prime }$ is evolved. The RHNs, being charged under $U(1{)}_X$ scenario, can explain the origin of observed baryon asymmetry through the resonant leptogenesis process. Applying observed neutrino oscillation data we study $Z^{\prime }$ and BSM scalar induced processes to reproduce the observed baryon asymmetry. Hence we estimate bounds on the $U(1{)}_X$ gauge coupling $(g_X)$ and the mass of the $Z^{\prime }$ $(M_{Z^{\prime }})$ for different $U(1{)}_X$ charges and benchmark masses of RHN and SM-singlet scalar. Finally we compare our results with limits obtained from the existing limits from LEP-II and LHC. We find that depending on the $U(1{)}_X$ charges, the masses of RHNs and SM-singlet scalar resonant leptogenesis could provide stronger limit on $g_X$ for $M_{Z^{\prime }}>5.8$ TeV which could be probed by high energy scattering experiment in future.

Comments: 13 pages, two figures