Equation of State for Neutralino Star as a Form of Cold Dark Matter

In order to study the structure of neutralino star and dark galaxy,we consider dynamical interactions due to boson-exchange in theneutralino matter. Taking into account interactions of neutralinoswith bosons, we derive the equation of state (EOS) of neutralino stars in terms of the relativistic mean-field approach. Then we apply the resulting EOS to investigate properties of the neutralino star such as its density profile and mass limit. For example, if the neutralino mass is around 1 TeV, the Oppenheimer mass limit of theneutralino star is obtained as 6.06×10^-7M_⊙, and the corresponding radius is about 7.8 mm. Actually, due to anincreasing annihilation rate as indicated by our calculation, thisdense state can never be realized in practice. Our results also showthat the low-density neutralino star may be a possible aggregationof the cold dark matter.