Theoretical direct WIMP detection rates for transitions to excited states

TL;DR

This paper presents a theoretical analysis of WIMP detection via transitions to low-lying excited nuclear states, highlighting potential experimental signatures such as gamma rays from de-excitation.

Contribution

It introduces a theoretical framework for direct WIMP detection focusing on inelastic scattering to excited nuclear states, expanding beyond traditional recoil detection methods.

Findings

Branching ratios for inelastic scattering are significant for certain nuclei.

Transition rates to excited states can be around 5% of ground state transitions for low-mass WIMPs.

Gamma-ray signatures from de-excitation could provide additional detection channels.

Abstract

The recent WMAP and Planck data have confirmed that exotic dark matter together with the vacuum energy (cosmological constant) dominate in the flat Universe. Many extensions of the standard model provide dark matter candidates, in particular Weakly Interacting Massive Particles (WIMPs). %Supersymmetry provides a natural dark matter candidate, the lightest supersymmetric particle (LSP). Thus the direct dark matter detection is central to particle physics and cosmology. Most of the research on this issue has hitherto focused on the detection of the recoiling nucleus. In this paper we study transitions to the excited states, possible in some nuclei, which have sufficiently low lying excited states. Good examples are the first excited states of I-127 and Xe-129. %focusing on the first excited state at 50 keV of Iodine A=127. We find appreciable branching ratios for the inelastic scattering mediated by the spin cross sections. %find that the transition rate to this excited state is about 5 %percent of the transition to the ground state for low mass WIMPS, but the branching ratio can be much larger in the case pf heaver WIMPS. So, in principle, the extra signature of the gamma ray following the de-excitation of these states can, in principle, be exploited experimentally.