Recent dark matter search results from the DarkSide-50 experiment using underground argon

by Alden Fan (UCLA)

Thursday 19 Nov 2015, 12:30 → 13:30 US/Pacific

Madrone (SLAC)

While there is tremendous astrophysical and cosmological evidence for dark matter, its precise nature is one of the biggest open questions in modern physics. Direct detection experiments are aiming to observe the scattering of WIMPs off normal matter. With the liquid noble technology leading the way in WIMP sensitivity, no conclusive signals have been observed yet. The DarkSide experiment is looking for WIMP dark matter using a liquid argon target located deep underground at Gran Sasso National Laboratory (LNGS) in Gran Sasso, Italy. DarkSide-50 is the first physics-capable detector in the DarkSide program, featuring a 50 kg active mass dual-phase Time Projection Chamber (TPC) surrounded by a 30 ton liquid scintillator neutron veto and a 1000 ton water-Cerenkov muon detector. The TPC is currently filled with argon obtained from underground sources, which is greatly reduced in radioactive 39Ar. DarkSide-50 recently made the most sensitive measurement of the 39Ar activity in underground argon and used it to set the strongest WIMP dark matter limit using liquid argon to date. Overviews of the DarkSide program and of the recent results from DarkSide-50 will be presented, as well as plans for next generation dual-phase liquid argon TPCs.