The ReD experiment for low-energy nuclear recoils in a liquid argon TPC(*)

Time Projection Chambers filled with Ar in double phase are largelyemployed in the direct detection of Weakly Interacting Massive Particles (WIMPs)as Dark Matter candidates. Models predict WIMP with a mass at the electroweakscale, so the expected energy of the Ar nuclear recoil after a WIMP-induced scatter-ing is in the range of tens of keV. However, if these particles had mass at the GeV/c2scale, the deposited energy would drop to a few keV. In this scenario, WIMP directdetection will become challenging but still possible in these detectors, as proved byrecent studies on the data collected by DarkSide-50. Since the future generationof multi-tonnes experiments aims to be sensitive also at this low-mass scale, theREcoil Directionality (ReD) experiment underwent a campaign to investigate theionization response of LAr down to a few keV.