Particle-antiparticle asymmetries from annihilations

Abstract

An extensively studied mechanism to create particle-antiparticle asymmetries is the out-of-equilibrium and CP violating decay of a heavy particle. Here we instead examine how asymmetries can arise purely from 2 <-> 2 annihilations rather than from the usual 1 <-> 2 decays and inverse decays. We review the general conditions on the reaction rates that arise from S-matrix unitarity and CPT invariance, and show how these are implemented in the context of a simple toy model. We formulate the Boltzmann equations for this model, and present an example solution.

5 pages, v2: added reference, v3: some changes to text in response to comments

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• Leptogenesis
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Cited by in corpus (1)

• The role of CP violating scatterings in baryogenesis - case study of the neutron portal