Consequences of f(R)-theories of gravity on gravitational leptogenesis

TL;DR

This paper explores how f(R) gravity theories influence gravitational leptogenesis, focusing on the role of Ricci scalar curvature in generating matter-antimatter asymmetry through heavy neutrino interactions.

Contribution

It analyzes specific f(R) models, such as R+αR^n and R^{1+ε}, to understand their impact on the gravitational leptogenesis mechanism.

Findings

Certain f(R) models can produce the necessary Ricci curvature variation for leptogenesis.

The study identifies conditions under which f(R) theories support matter-antimatter asymmetry.

Results suggest f(R) gravity can be compatible with observed baryon asymmetry.

Abstract

f(R)-theories of gravity are reviewed in the framework of the matter-antimatter asymmetry in the Universe. The asymmetry is generated by the gravitational coupling of heavy (Majorana) neutrinos with the Ricci scalar curvature. In order that the mechanism works, a time varying non-zero Ricci curvature is necessary. The latter is provided by f(R) cosmology, whose Lagrangian density is of the form {\cal L}(R)\sim f(R). In particular we study the cases f(R)\sim R+\alpha R^n and f(R)\sim R^{1+\epsilon}.