Constraining the mSUGRA (minimal supergravity) parameter space using the entropy of dark matter halos

We derive an expression for the entropy of a dark matter halo described using a Navarro–Frenk–White model with a core. The comparison of this entropy with that of dark matter in the freeze-out era allows us to constrain the parameter space in mSUGRA models. Moreover, combining these constraints with the ones obtained from the usual abundance criterion and demanding that these criteria be consistent with the 2σ bounds for the abundance of dark matter: 0.112≤ΩDMh2≤0.122, we are able to clearly identify validity regions among the values of tanβ, which is one of the parameters of the mSUGRA model. We found that for the regions of the parameter space explored, small values of tanβ are not favored; only for are the two criteria significantly consistent. In the region where the two criteria are consistent we also found a lower bound for the neutralino mass, mχ≥141 GeV.