Neutrino Constraints on Inelastic Dark Matter after CDMS II

TL;DR

This paper examines how neutrino observations from the Sun and Earth constrain inelastic dark matter models that aim to reconcile DAMA/LIBRA results with other experiments, focusing on annihilation channels and mass parameters.

Contribution

It provides updated neutrino-based constraints on inelastic dark matter models, considering recent CDMS II data and exploring the impact of different annihilation channels and mass splittings.

Findings

Super-Kamiokande excludes certain annihilation channels like W+W-, ZZ, t-tbar, and tau+ tau-.

Future IceCube plus DeepCore can test or constrain soft channels such as b-bbar and c-cbar.

Constraints on Earth-based annihilation are limited to small mass splittings and specific mass ranges.

Abstract

We discuss the neutrino constraints from solar and terrestrial dark matter (DM) annihilations in the inelastic dark matter (iDM) scenario after the recent CDMS II results. To reconcile the DAMA/LIBRA data with constraints from all other direct experiments, the iDM needs to be light ($m_\chi < 100$ GeV) and have a large DM-nucleon cross section ($\sigma_n \sim$ 10$^{-4}$ pb in the spin-independent (SI) scattering and $\sigma_n \sim$ 10 pb in the spin-dependent (SD) scattering). The dominant contribution to the iDM capture in the Sun is from scattering off Fe/Al in the SI/SD case. Current bounds from Super-Kamiokande exclude the hard DM annihilation channels, such as $W^+W^-$, $ZZ$, $t\bar{t}$ and $\tau^+ \tau^-$. For soft channels such as $b\bar{b}$ and $c \bar{c}$, the limits are loose, but could be tested or further constrained by future IceCube plus DeepCore. For neutrino constraints from the DM annihilation in the Earth, due to the weaker gravitational effect of the Earth and inelastic capture condition, the constraint exists only for small mass splitting $\delta <$ 40 keV and $m_\chi \sim (10, 50)$ GeV even in the $\tau^+ \tau^-$ channel.