Search for low-mass dark matter WIMPs with 12 ton-day exposure of DarkSide-50

TL;DR

This paper reports a new analysis of DarkSide-50 data, setting improved limits on low-mass WIMP dark matter particles below 10 GeV/c², using enhanced calibration and background modeling to extend exclusion regions.

Contribution

The study introduces a more accurate calibration and background model, significantly improving the sensitivity for low-mass WIMP detection compared to previous DarkSide-50 results.

Findings

Set a 90% C.L. exclusion limit of 6×10⁻⁴³ cm² for 3 GeV/c² WIMPs

Extended exclusion region for WIMPs in the 1.2–3.6 GeV/c² mass range

Achieved background modeling down to 0.06 keVₑᵣ with improved systematic uncertainties

Abstract

We report on the search for dark matter WIMPs in the mass range below 10 GeV/c$^2$, from the analysis of the entire dataset acquired with a low-radioactivity argon target by the DarkSide-50 experiment at LNGS. The new analysis benefits from more accurate calibration of the detector response, improved background model, and better determination of systematic uncertainties, allowing us to accurately model the background rate and spectra down to 0.06 keV$_{er}$. A 90% C.L. exclusion limit for the spin-independent cross section of 3 GeV/c$^2$ mass WIMP on nucleons is set at 6$\times$10$^{-43}$ cm$^2$, about a factor 10 better than the previous DarkSide-50 limit. This analysis extends the exclusion region for spin-independent dark matter interactions below the current experimental constraints in the $[1.2, 3.6]$ GeV/c$^2$ WIMP mass range.