A test of the standard dark matter density evolution law using galaxy
  clusters and cosmic chronometers
  In this letter, we implement a test of the standard law for the dark matter
density evolution. For this purpose, only a flat universe and the validity of
the FRW metric are assumed. A deformed dark matter density evolution law is
considered, given by $\rho_c(z) \propto (1+z)^{3+\epsilon}$, and constraints on
$\epsilon$ are obtained by using galaxy cluster gas mass fractions, and cosmic
chronometers measurements. We find that $\epsilon =0$ within 2$\sigma$ c.l., in
full agreement with other recent analyses.
