HEP Theory Journal Club

On the double-counting problem in Boltzmann equations and real-intermediate state subtraction

Michael Laplante

McGill

Progress in baryogenesis has led to the now well explored electroweak baryogenesis and leptogenesis mechanisms. These rely on numerically solving a set of classical differential equations (Boltzmann equations) in which we implement the probabilities of quantum processes. This merging of classical and quantum formalisms gives rise to a double-counting problem: a scattering process leading to an on-shell intermediate state is indistinguishable from an inverse decay followed by a decay. In this talk, we will review the different ways in which the community has dealt with this issue, and why it is not obvious which of these approaches (if any) is correct.