Baryogenesis from Oscillations of Charmed or Beautiful Baryons

TL;DR

This paper introduces a new model where CP-violating oscillations of heavy baryons could explain the matter-antimatter asymmetry in the universe, with testable predictions at collider experiments.

Contribution

It proposes a novel baryogenesis mechanism involving heavy baryon oscillations and outlines a testable parameter space at Belle II.

Findings

Parameters where baryon oscillations generate observed asymmetry

Suppression of neutron oscillations and nuclear decays

Potential collider signatures of new particles

Abstract

We propose a model for CP violating oscillations of neutral, heavy-flavored baryons into antibaryons at rates which are within a few orders of magnitude of their lifetimes. The flavor structure of the baryon violation suppresses neutron oscillations and baryon number violating nuclear decays to experimentally allowed rates. We also propose a scenario for producing such baryons in the early Universe via the out-of-equilibrium decays of a neutral particle, after hadronization but before nucleosynthesis. We find parameters where CP violating baryon oscillations at a temperature of a few MeV could result in the observed asymmetry between baryons and antibaryons. Furthermore, part of the relevant parameter space for baryogenesis is potentially testable at Belle II via decays of heavy flavor baryons into an exotic neutral fermion. The model introduces four new particles: three light Majorana fermions and a colored scalar. The lightest of these fermions is typically long lived on collider timescales and may be produced in decays of bottom and possibly charmed hadrons.