Asymmetric Self-interacting Dark Matter and Neutrino Mass via Dirac Leptogenesis

¹ Department of Physics, North Lakhimpur University, Khelmati, North Lakhimpur, Lakhimpur, Assam 787031, India
² Indian Association for the Cultivation of Science (IACS), Kolkata, Jadavpur, 700032, West Bengal, India

^* e-mail: dutta.manoranjan@nlc.ac.in
^** e-mail: nimmalanarendra@gmail.com

Published online: 20 November 2024

Abstract

We propose a framework to address the observed baryon asymmetry considering neutrinos as Dirac particles and dark matter to be self-interacting. The Standard Model is extended by U(1)_B−L × U(1)_D symmetry. In addition to the three right-handed neutrinos, the Standard Model particle content is extended by two more fermion fields; one of them is a S U(2) singlet and the other one is S U(2) doublet, both charged under the extended symmetry. A Z₂ symmetry is imposed under which the doublet is positive while the singlet is negative. The singlet, being the lightest dark sector particle, acts as the dark matter. The U(1)_D symmetry of the dark sector is spontaneously broken and the corresponding gauge boson Z′ not only mediates the self-interaction among dark matter particles, but also facilitates the annihilation of the symmetric component of dark matter. CP-violating out of equilibrium decay of another heavy Z₂ odd S U(2) scalar doublet N into leptonic and dark sectors produce the observed baryon asymmetry and dark matter density. Moreover, Z′ also mixes with the standard model Z-boson opening up a portal for the direct detection of dark matter.