Leptogenesis and gravity: baryon asymmetry without decays

Abstract

A popular class of theories attributes the matter-antimatter asymmetry of the Universe to CP-violating decays of super-heavy BSM particles in the Early Universe. Recently, we discovered a new source of leptogenesis in these models, namely that the same Yukawa phases which provide the CP violation for decays, combined with curved-spacetime loop effects, lead to an entirely new gravitational mechanism for generating an asymmetry, driven by the expansion of the Universe and independent of the departure of the heavy particles from equilibrium. In this Letter, we build on previous work by analysing the full Boltzmann equation, exploring the full parameter space of the theory and studying the time-evolution of the asymmetry. Remarkably, we find regions of parameter space where decays play no part at all, and where the baryon asymmetry of the Universe is determined solely by gravitational effects.

Journal version, published in Phys. Lett. B

References in corpus (1)

• Leptogenesis from loop effects in curved spacetime

Cited by in corpus (9)

• Non-thermal Origin of Asymmetric Dark Matter from Inflaton and Primordial Black Holes
• Flavour effects in gravitational leptogenesis
• Dynamical Evolution of Gravitational Leptogenesis
• Instability of gravitational baryogenesis with fermions
• Testing Fundamental Physics in Antihydrogen Experiments
• A New Twist on the Geometry of Gravitational Plane Waves
• Gravitational charge production
• Gravitational wave complementarity and impact of NANOGrav data on gravitational leptogenesis: cosmic strings
• A Model of Gravitational Leptogenesis