Gravitational Baryogenesis in Extended Proca-Nuevo Gravity

Abstract: In this article, we investigate the gravitational baryogenesis mechanism in the framework of Extended Proca-Nuevo (EPN) gravity, a theory where a massive vector field is non-minimally coupled to the curvature. This analysis is carried out for an early universe, encompassing three separate cosmological scenarios defined by power-law, exponential, and modified exponential scale factors. By deriving the modified field equations from the EPN action, we obtain precise solutions for each scale factor, including the influence of the vector field. We compute the baryon-to-entropy ratio using the gravitational baryogenesis formalism, where the baryon asymmetry arises from a dynamical coupling of the baryon current with the derivative of the Ricci scalar. Our findings demonstrate that the baryon-to-entropy ratio is consistent with observational constraints in all scenarios, highlighting the potential of EPN gravity as a viable theory to explain the matter-antimatter asymmetry in the early universe. The study further stresses the contribution of anisotropy and vector field dynamics to the cosmological evolution within modified gravity models.