Direct baryogenesis in the broken phase

TL;DR

This paper proposes a novel baryogenesis mechanism occurring in the broken phase at temperatures below the electroweak scale, involving flavor oscillations and baryon number violation via a dimension nine operator.

Contribution

It introduces a new baryogenesis scenario where baryon asymmetry is generated through scatterings mediated by a high-dimension operator at low reheating temperatures.

Findings

Baryon asymmetry can be produced below the electroweak scale.

The mechanism involves flavor oscillations of high-energy quarks.

Testable predictions include neutron-antineutron oscillations.

Abstract

We show a new mechanism for baryogenesis where the reheating temperature can be smaller than the electroweak scale. The baryon number symmetry is violated by a dimension nine operator which conserves a baryon parity. A high energy quark from the decay of a heavy particle, $e.g.$ inflaton, modulus or gravitino, undergoes flavor oscillation, and is thermalized due to the scatterings with the ambient thermal plasma. We point out that the baryon asymmetry of our universe can be generated due to the scatterings via the baryon number violating operator. Our scenario can be tested in neutron-antineutron oscillation experiments as well as other terrestrial experiments.