Prospects For Detecting Dark Matter With Neutrino Telescopes In Light Of Recent Results From Direct Detection Experiments

TL;DR

The paper investigates how neutrino telescopes can probe dark matter through WIMP annihilation in the Sun, even after stringent direct-detection bounds from experiments like CDMS. It develops a model-independent capture–annihilation framework and then applies it to two specific DM candidates: MSSM neutralinos and KK dark matter in UED. The findings show that spin-dependent WIMP–proton interactions often dominate solar capture and can yield strong neutrino signals, with neutralinos having detectable IceCube rates in many viable parameter regions and KK dark matter offering modest yet non-negligible signals within thermal relic scenarios. Overall, neutrino telescopes provide a complementary and sometimes superior window into certain DM models, extending the reach of the dark matter search beyond what direct detection alone can achieve.

Abstract

Direct detection dark matter experiments, lead by the CDMS collaboration, have placed increasingly stronger constraints on the cross sections for elastic scattering of WIMPs on nucleons. These results impact the prospects for the indirect detection of dark matter using neutrino telescopes. With this in mind, we revisit the prospects for detecting neutrinos produced by the annihilation of WIMPs in the Sun. We find that the latest bounds do not seriously limit the models most accessible to next generation kilometer-scale neutrino telescopes such as IceCube. This is largely due to the fact that models with significant spin-dependent couplings to protons are the least constrained and, at the same time, the most promising because of the efficient capture of WIMPs in the Sun. We identify models where dark matter particles are beyond the reach of any planned direct detection experiments while within reach of neutrino telescopes. In summary, we find that, even when contemplating recent direct detection results, neutrino telescopes still have the opportunity to play an important as well as complementary role in the search for particle dark matter.

Figures (6)

• Figure 1: The event rate in a kilometer-scale neutrino telescope as a function of the WIMP's effective elastic scattering cross section in the Sun for a variety of annihilation modes. The effective elastic scattering cross section is defined as $\sigma_{\rm{eff}} = \sigma_{\mathrm{H, SD}} +\, \sigma_{\mathrm{H, SI}} + 0.07 \, \sigma_{\mathrm{He, SI}}$, following Eq. \ref{['capture']}. The dashes, solid and dotted lines correspond to WIMPs of mass 100, 300 and 1000 GeV, respectively. A 50 GeV muon energy threshold has been used. An annihilation cross section of $3 \times 10^{-26}$ cm$^-3$ s$^{-1}$ has been assumed. If another annihilation cross section were used, the change in the slope of these contours would occur at different location.
• Figure 2: The lightest neutralino's spin-independent (left) and spin-dependent (right) scattering cross sections for a range of MSSM parameters. See text for more details.
• Figure 3: A comparison of the spin-dependent and spin-independent scattering cross sections for neutralinos in the MSSM. See text for more details.
• Figure 4: The rate of events at a kilometer-scale neutrino telescope from dark matter annihilations in the Sun, as a function of the WIMP's spin-dependent elastic scattering cross section. In the left frame, no points shown violate the current spin-independent scattering constraints of CDMS. In the right frame, no points would violate the a spin-independent bound 100 times stronger. See text for more details.
• Figure 5: In the left frame, the spin-dependent elastic scattering cross section of the lightest neutralino with protons is shown as a function of the quantity $|f_{H_1}|^2 - |f_{H_2}|^2$. In the right frame, the rate in a kilometer-scale neutrino telescope is shown, using a muon energy threshold of 50 GeV. Each point shown evades the current constraint of CDMS. See text for more details.