Probing dark matter self-interaction in the Sun with IceCube-PINGU

Abstract

We study the capture, annihilation and evaporation of dark matter (DM) inside\nthe Sun. It has been shown that the DM self-interaction can increase the DM\nnumber inside the Sun. We demonstrate that this enhancement becomes more\nsignificant in the regime of small DM mass, given a fixed DM self-interaction\ncross section. This leads to the enhancement of neutrino flux from DM\nannihilation. On the other hand, for DM mass as low as a few GeVs, not only the\nDM-nuclei scatterings can cause the DM evaporation, DM self-interaction also\nprovides non-negligible contributions to this effect. Consequently, the\ncritical mass for DM evaporation (typically 3 $\\sim$ 4 GeV without the DM\nself-interaction) can be slightly increased. We discuss the prospect of\ndetecting DM self-interaction in IceCube-PINGU using the annihilation channels\n$\\chi\\chi \\rightarrow \\tau^{+}\\tau^{-}, \\nu\\bar{\\nu}$ as examples. The PINGU\nsensitivities to DM self-interaction cross section $\\sigma_{\\chi\\chi}$ are\nestimated for track and cascade events.\n