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arXiv · 2302.11442

$CPT$ and unitarity constraints for higher-order $CP$ asymmetries at finite temperature

Tomáš Blažek·Peter Maták·Viktor Zaujec
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Abstract

We use an unconventional diagrammatic approach to formulate $CPT$ and unitarity constraints for higher-order $CP$ asymmetries entering the source term in the Boltzmann equation. Usually, the reaction rate asymmetries in these constraints are computed within the classical kinetic theory, using zero-temperature quantum field theory to describe particles' interactions. We approximate the rates, otherwise obtained within the closed-time-path formalism, in terms of diagrams drawn on a cylindrical surface and their holomorphic cuts. The resulting equilibrium asymmetry constraints incorporate thermal-mass effects and allow tracking the cancellations of reaction rate asymmetries computed with quantum statistics. We use the top Yukawa corrections to the asymmetries in the seesaw type-I leptogenesis as an example.

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Tomáš Blažek, Peter Maták, Viktor Zaujec. 2023-02-22. $CPT$ and unitarity constraints for higher-order $CP$ asymmetries at finite temperature. https://doi.org/10.22323/1.431.0027

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