Seminaria Instytutowe

Is Dark Matter getting a little lighter?

by Dr Władysław Trzaska (University of Jyväskylä, Finland)


First postulated a century ago, Dark Matter still defies our attempts to confirm its existence and determine its nature. Most terrestrial DM searches focus on direct detection via elastic scattering on cryogenic targets. I’ll compare these results with the puzzling outcome of the new analysis of indirect searches from several underground experiments. These measurements, performed at various depths by different groups using diverse methods, yield persistent anomalous structures with comparable cross-sections, rates, and multiplicities. The nature of the anomalies remains unclear, but, in principle, they may be a signature of self-annihilation of a Weakly Interacting Massive Particle (WIMP) with a mass ~10 GeV/c2. With that assumption, the expected cross-section would be of the order of 10^-42 cm2 for Spin-Dependent or 10^-46 cm2 for Spin Independent interactions. We propose verifying this hypothesis by collecting an order of magnitude more data with an upgraded NEMESIS setup located in the Pyhäsalmi mine in Finland. Based on the statistical uncertainty, analysis of the event rate indicates that such a setup can probe cross-section limits for DM masses in the vicinity of 3-40 GeV/c2.

The first results of our investigations were presented at ICRC 2021 and TAUP 2021 conferences. The proceedings are in print. There is also a 12-minute YouTube video showing the experimental setup and briefly introducing the outcome of the measurements: