Analysis of a possible explanation of the positron anomaly in terms of dark matter

Abstract

The possibility of explaining the positron anomaly on the basis of models involving the darkmatter annihilation or decay is being widely discussed at the present time. However, such models are severely constrained by data on cosmic gamma radiation. Two different procedures that rely on the χ2 criterion and which permit taking this constraint into account are considered in the present study. In one case, the use of positron data alone in searches for a minimum value of χ2 via varying model parameters is followed by a comparison with gamma-radiation data. In the second case, the χ2 functional is minimized by simultaneously employing positron and gamma-radiation data, whereby a more lenient (more “flexible”) constraint is obtained. Nevertheless, either procedure rules out the possibility of explaining the positron anomaly in terms of unstable dark matter distributed over the whole halo. The assumption that the dark-matter component undergoing annihilation (decay) is concentrated within the galactic disk makes it possible to remove the constraint in either case.