Standard Model extension with gravity and gravitational baryogenesis

Gaetano Lambiase

doi:10.1016/j.physletb.2006.09.037

Abstract

Abstract The Standard Model extension with the inclusion of gravity is studied in the framework of the gravitational baryogenesis, a mechanism to generate the baryon asymmetry based on the coupling between the Ricci scalar curvature and the baryon current ( ∂ μ R ) J μ . We show that, during the radiation era of the expanding universe, a non-vanishing time derivative of the Ricci curvature arises as a consequence of the coupling between the coefficients for the Lorentz and CPT violation and Ricci's tensor. The order of magnitude for these coefficients are derived from current bounds on baryon asymmetry.

Highlights

The Standard Model Extension with the inclusion of gravity is studied in the framework of the gravitational baryogenesis, a mechanism to generate the baryon asymmetry based on the coupling between the Ricci scalar curvature and the baryon current (∂μR)Jμ
Referring to Lorentz’s and CPT symmetries, the more general setting in which they have been studied is the Standard Model Extension (SME) [1]. The violation of such fundamental symmetries follows from the observation that the vacuum solution of the theory could spontaneously violate the Lorentz and CPT invariance, even though them are preserved by the underlying theory
The origin of the the baryon number asymmetry is an open issue of the modern Cosmology and particle physics

Summary

Introduction

The Standard Model Extension with the inclusion of gravity is studied in the framework of the gravitational baryogenesis, a mechanism to generate the baryon asymmetry based on the coupling between the Ricci scalar curvature and the baryon current (∂μR)Jμ. It is argued that to generate (dynamically) the baryon asymmetry from an initial symmetric phase the following requirements are necessary [11]: 1) baryon number processes violating in particle interactions; 2) C and CP Violation in order that processes generating B are more rapid with respect to B; 3) out of the equilibrium: since mB = mB, as follows from CP T symmetry, the equilibrium space phase density of particles and antiparticles are the same.

Results

Conclusion