Minimal Flavor Violation in the Minimal U(1)_{B-L} Model and Resonant Leptogenesis

TL;DR

This paper explores how minimal flavor violation in a TeV-scale $U(1)_{B-L}$ extended model enables resonant leptogenesis, producing the observed baryon asymmetry with potential LHC detectability.

Contribution

It introduces a minimal flavor violation framework in a $U(1)_{B-L}$ model that naturally enhances CP asymmetry for resonant leptogenesis at TeV scales.

Findings

Achieves correct baryon asymmetry via thermal leptogenesis.

Shows potential for discovering $U(1)_{B-L}$ gauge boson at LHC.

Demonstrates automatic mass splitting due to tiny Dirac Yukawa coupling.

Abstract

We investigate the resonant leptogenesis scenario in the minimally $U(1)_{B-L}$ extended standard model with minimal flavor violation. In our model, the $U(1)_{B-L}$ gauge symmetry is broken at the TeV scale and standard model singlet neutrinos gain Majorana masses of order TeV. In addition, we introduce a flavor symmetry on the singlet neutrinos at a scale higher than TeV. The flavor symmetry is explicitly broken by the neutrino Dirac Yukawa coupling, which induces splittings in the singlet neutrino Majorana masses at lower scales through renormalization group evolutions. We call this setup "minimal flavor violation". The mass-splittings are proportional to the tiny Dirac Yukawa coupling, and hence they automatically enhance the CP asymmetry parameter necessary for the resonant leptogenesis mechanism. In this paper, we calculate the baryon number yield by solving the Boltzmann equations, including the effects of $U(1)_{B-L}$ gauge boson that also has TeV scale mass and causes washing-out of the singlet neutrinos in the course of thermal leptogenesis. The Dirac Yukawa coupling for neutrinos is fixed in terms of neutrino oscillation data and an arbitrary $3 \times 3$ complex-valued orthogonal matrix. We show that the right amount of baryon number asymmetry can be achieved through thermal leptogenesis in the context of the minimal flavor violation with singlet neutrinos and $U(1)_{B-L}$ gauge boson at the TeV scale. These particles can be discovered at the LHC in the near future.