Unitarity constraints on asymmetric freeze-in
arXiv:1105.3728 · doi:10.1103/PhysRevD.84.055003
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.
15 pages, 7 figures, change in notation, accepted to prd