  We investigate a novel interplay between the decay and annihilation of a
particle whose mass undergoes a large shift during a first order phase
transition, leading to the particles becoming trapped in the false vacuum and
enhancing their annihilation rates as the bubbles of true vacuum expand. This
opens up a large region of the parameter space where annihilations can be
important. We apply this scenario to baryogenesis, where we find that
annihilations can be enhanced enough to generate the requires baryon asymmetry
even for relatively tiny annihilation cross sections with modest CP
asymmetries.

High Energy Physics - Phenomenology