First Results from the DarkSide-50 Dark Matter Experiment at Laboratori Nazionali del Gran Sasso

TL;DR

DarkSide-50 conducted the most sensitive argon-based direct dark matter search to date, using a liquid argon detector underground at LNGS, but found no evidence of WIMP interactions, setting new upper limits on cross sections.

Contribution

First results from DarkSide-50 demonstrate a highly sensitive argon detector for dark matter, establishing new upper limits on WIMP-nucleon interactions with null detection.

Findings

No dark matter signal detected in 1422 kg·d exposure.

Set a 90% CL upper limit on WIMP-nucleon cross section of 6.1×10^-44 cm^2 at 100 GeV/c^2.

Achieved the most sensitive argon-based dark matter search to date.

Abstract

We report the first results of DarkSide-50, a direct search for dark matter operating in the underground Laboratori Nazionali del Gran Sasso (LNGS) and searching for the rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs). The dark matter detector is a Liquid Argon Time Projection Chamber with a (46.4+-0.7) kg active mass, operated inside a 30 t organic liquid scintillator neutron veto, which is in turn installed at the center of a 1 kt water Cherenkov veto for the residual flux of cosmic rays. We report here the null results of a dark matter search for a (1422+-67) kg d exposure with an atmospheric argon fill. This is the most sensitive dark matter search performed with an argon target, corresponding to a 90% CL upper limit on the WIMP-nucleon spin-independent cross section of 6.1x10^-44 cm^2 for a WIMP mass of 100 GeV/c^2.