Freed Leptogenesis

TL;DR

This paper explores how loop effects in extended Standard Model scenarios can relax the constraints on neutrino masses and CP asymmetry, potentially addressing leptogenesis and dark matter issues.

Contribution

It introduces a model where loop effects relax the Davidson-Ibarra bound, allowing lower heavy neutrino masses and higher light neutrino masses, with implications for dark matter.

Findings

Relaxation of the Davidson-Ibarra bound due to loop effects

Lower bounds on heavy neutrino masses are decreased

Upper bounds on light neutrino masses are increased

Abstract

Economical extensions of the Standard Model (SM), in which the famous Davidson-Ibarra bound on the CP asymmetry relevant for leptogenesis may be significantly relaxed by the loop effects, comparing to predictions of the SM extended only by right-handed neutrinos with hierarchical masses, are discussed. This leads to decreasing of the lower bound on the heavy neutrino masses and increasing of the upper bound on the light neutrino masses. In addition, the considered theory may help to solve the dark matter problem.