Search for the inelastic scattering of weakly interacting massive particles on the 178m2Hf isomer

Abstract

The results of the second experimental search for dark matter using the ^178m2Hf isomer are presented. The high-energy γ-rays that cannot be emitted during the spontaneous decay of this isomer but might arise from the population of excited nuclear levels in ¹⁷⁸Hf due to the inelastic scattering with dark matter particles are analyzed in detail. The limits on the half-life of the dark-matter-induced transitions, obtained from limits on these γ-ray intensities, have reached T_1/2 > 9.3 × 10⁵ years. Further progress of such experimental efforts is discussed.