Unitarity constraints on asymmetric freeze-in

TL;DR

This paper explores how unitarity and CPT constraints affect asymmetric freeze-in mechanisms for baryon asymmetry, revealing that baryon transfer cancels at leading order due to fundamental symmetries.

Contribution

It demonstrates that unitarity and CPT impose unexpected cancellations in asymmetric freeze-in, impacting baryon number transfer calculations.

Findings

Baryon transfer cancels at leading order due to symmetry constraints.

Unitarity and CPT lead to cancellations in asymmetric freeze-in.

Implications for baryogenesis models using freeze-in mechanisms.

Abstract

This paper considers unitarity and CPT constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov's out of equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and CPT lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order.