Search for Dark Matter Annihilations in the Sun with the 79-String IceCube Detector

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range $20–5000\mathrm{GeV}/c^2$. These are the most stringent spin-dependent WIMP-proton cross section limits to date above $35\mathrm{GeV}/c^2$ for most WIMP models.

Figure 1

Cosine of the angle between the reconstructed track and the direction of the Sun $\Psi$ for observed events (squares), with 1 standard deviation error bars and the atmospheric background expectation from atmospheric muons and neutrinos (dashed line). Also shown is a simulated signal ($1\mathrm{TeV}/c^2$ hard for data set WH, $50\mathrm{GeV}/c^2$ hard for data sets WL and SL) scaled to ${\mu }_s^{90}$ (details are given in Table 1).

Figure 2

90% C.L. upper limits on ${\sigma }_{\mathrm{SI},p}$ (top figure) and ${\sigma }_{\mathrm{SD},p}$ (bottom figure) for hard and soft annihilation channels over a range of WIMP masses. Systematic uncertainties are included. The shaded region represents an allowed minimal supersymmetric standard model parameter space (MSSM-25 [42]) taking into account recent accelerator [43], cosmological, and direct DM search constraints. The results from Super-K [28], COUPP (exponential model) [29], PICASSO [30], CDMS [31, 32], XENON100 (limits above $1\mathrm{TeV}/c^2$ from the XENON100 Collaboration) [36], CoGeNT [35], Simple [37], and DAMA [33, 34] are shown for comparison.