Dynamical Relaxation of the Dark Matter to Baryon Ratio

Abstract

A scalar field interacting differently with dark matter and baryons may explain why their ratio is of order unity today. We provide three working examples, checking them against the observations of CMB, Large Scale Structure, supernovae Ia, and post-newtonian tests of gravity. Such a scenario could make life much easier for supersymmetric dark matter candidates.

Comments: 7 pages, 5 .eps figures. Discussion of the approach of the field to the fixed point added. Figures modified accordingly. Conclusions unchanged. Version to be published on Phys Rev. D