Search for Dark Matter WIMPs using Upward Through-going Muons in Super-Kamiokande

TL;DR

This study conducts an indirect search for WIMP dark matter using neutrino-induced upward muons in Super-Kamiokande, focusing on annihilations in the Sun, Earth, and Galactic Center with $m_\chi$ spanning $18\,\mathrm{GeV}$ to $10\,\mathrm{TeV}$. Analyzing 1679.6 live days, the authors find no significant excess above atmospheric backgrounds and establish 90% CL flux limits for various cone angles, subsequently deriving conservative WIMP-nucleon cross-section limits for both scalar and axial-vector couplings. By employing a model-independent framework comparing direct and indirect detection rates via the parameter $\xi(m_\chi)$, they compare with direct-detection experiments and show that Super-K limits exclude portions of the DAMA-favored region, while providing ~100× stronger constraints on the WIMP-proton cross-section. The results demonstrate the complementary value of indirect detection and substantially constrain SUSY parameter space relevant to dark matter searches.

Abstract

We present the results of indirect searches for Weakly Interacting Massive Particles (WIMPs) with 1679.6 live days of data from the Super-Kamiokande detector using neutrino-induced upward through-going muons. The search is performed by looking for an excess of high energy muon neutrinos from WIMP annihilations in the Sun, the core of the Earth, and the Galactic Center, as compared to the number expected from the atmospheric neutrino background. No statistically significant excess was seen. We calculate flux limits in various angular cones around each of the above celestial objects. We obtain conservative model-independent upper limits on WIMP-nucleon cross-section as a function of WIMP mass and compare these results with the corresponding results from direct dark matter detection experiments.

Figures (14)

• Figure 1: Zenith angle distribution of upward through-going muons with respect to the center of the Earth along with comparison against the expected flux. The black circles indicate observed data along with statistical uncertainties. Hatched regions indicates the background from atmospheric neutrinos, the solid lines indicate the atmospheric neutrino background after taking into account neutrino oscillations with: $\sin^2 2{\theta} = 1.0$ and $\Delta \hbox{m}^2 =2 \times 10^{-3} \hbox{eV}^{2}.$ The hatched region in $-1.0<cos(\Theta)<-0.866$ range indicates the angular region where WIMP searches were done.
• Figure 2: Angular distribution of upward through-going muons with respect to the Sun. All symbols are same as in Fig. \ref{['fig-1']}.
• Figure 3: Angular distribution of upward through-going muons with respect to the Galactic Center. All symbols are same as in Fig. \ref{['fig-1']}.
• Figure 4: The expanded view of the zenith angle distribution of upward through-going muons around the Earth's center (Fig. \ref{['fig-1']}). All symbols are same as in Fig. \ref{['fig-1']}.
• Figure 5: The expanded view of the angular distribution of upward through-going muons around the Sun (Fig. \ref{['fig-2']}). All symbols are same as in Fig. \ref{['fig-1']}.