A precision test of the nature of Dark Matter and a probe of the QCD phase transition

Abstract

If dark matter (DM) contains equal numbers of u,d,s quarks, the ratio of DM and ordinary matter densities is shown to follow from the Boltzmann distribution in the Quark Gluon Plasma. For sexaquark DM in the 1860-1880 MeV mass range (assuring sexaquark and nuclear stability) and quark masses and transition temperature from lattice QCD, the observed Omega_{DM}/Omega_b = 5.3 is in the predicted range, with <~ 15% uncertainty. The prediction is insensitive to the current form of DM, which could be sexaquarks, strange quark matter nuggets, primordial black holes from their collapse, or a mixture of these.

Comments: v3: Fig. 2 is replaced, correcting a plotting bug. v2: Reorganizes to improve clarity, adds discussion of detection constraints; shows that the small breakup cross section required for survival below T=150 degrees is compatible with expectations. Thus the claim by Kolb and Turner that dibaryons cannot be the dark matter does not appoy to the proposed sexaquark dark matter model