Theoretical direct WIMP detection rates for transitions to nuclear excited states

TL;DR

This paper investigates the detection of dark matter WIMPs through inelastic scattering to nuclear excited states, focusing on $^{83}$Kr, and finds promising signatures via gamma rays for experimental detection.

Contribution

It introduces a theoretical analysis of inelastic WIMP-nucleus scattering to excited states, especially for $^{83}$Kr, highlighting potential experimental signatures.

Findings

Appreciable branching ratios for inelastic scattering via spin cross sections.

Estimated inelastic event rate of 4.4×10⁻⁴ kg⁻¹ day⁻¹ for $^{83}$Kr.

Potential for gamma-ray detection as an additional signature.

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). 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. Examples considered previously were the first excited states of $^{127}$I and $^{129}$Xe. We examine here $^{83}$Kr, which offers some kinematical advantages and is currently considered as a possible target. We find appreciable branching ratios for the inelastic scattering mediated by the spin cross sections, with an inelastic event rate of $4.4\times 10^{-4}$kg$^{-1}$d$^{-1}$. So, the extra signature of the gamma ray following the de-excitation of these states can, in principle, be exploited experimentally. A brief discussion of the experimental feasibility is given