The New DAMA Dark-Matter Window and Energetic-Neutrino Searches

TL;DR

This paper explores the DAMA dark-matter detection claim, analyzing how neutrino searches from the Sun can constrain light WIMP models, and finds that existing neutrino limits significantly restrict the DAMA-allowed parameter space.

Contribution

It introduces a method to use neutrino flux limits from Super-Kamiokande to constrain light WIMP models consistent with DAMA's signal, especially for spin-dependent interactions.

Findings

Super-Kamiokande neutrino limits exclude a large portion of the DAMA region.

Constraints are especially strong for WIMPs producing tau leptons or neutrinos.

Any self-annihilating WIMP in the DAMA region with >1% annihilation to neutrinos or leptons is excluded.

Abstract

Recently, the DAMA/LIBRA collaboration has repeated and reinforced their claim to have detected an annual modulation in their signal rate, and have interpreted this observation as evidence for dark-matter particles at the 8.2 sigma confidence level. Furthermore, it has also been noted that the effects of channeling may enable a WIMP that scatters elastically via spin-independent interactions from nuclei to produce the signal observed by DAMA/LIBRA without exceeding the limits placed by CDMS, XENON, CRESST, CoGeNT and other direct-detection experiments. To accommodate this signal, however, the mass of the responsible dark-matter particle must be relatively light, m_{DM} \lsim 10 GeV. Such dark-matter particles will become captured by and annihilate in the Sun at very high rates, leading to a potentially large flux of GeV-scale neutrinos. We calculate the neutrino spectrum resulting from WIMP annihilations in the Sun and show that existing limits from Super-Kamiokande can be used to close a significant portion of the DAMA region, especially if the dark-matter particles produce tau leptons or neutrinos in a sizable fraction of their annihilations. We also determine the spin-dependent WIMP-nuclei elastic-scattering parameter space consistent with DAMA. The constraints from Super-Kamiokande on the spin-dependent scenario are even more severe--they exclude any self-annihilating WIMP in the DAMA region that annihilates 1% of the time or more to any combination of neutrinos, tau leptons, or charm or bottom quarks.