Speaker
Description
DarkSide-50 is a direct dark matter search experiment using a dual phase argon time projection chamber filled with low-radioactivity underground argon. Based solely on the ionization spectrum, it has set the most stringent exclusion limits for several low-mass dark matter candidates. Such analyses suffer from so-called spurious electron (SE) events at the lowest detectable energy region and are prevented from exploring the most sensitive part for low-mass dark matter searches. This presentation focuses on the progress toward understanding of the spurious electron background. It is indicated that a significant fraction of the SE events is related to the impurities in the TPC. While a full understanding of the source of the SE events will require dedicated R&D, possible mechanisms and mitigation strategies are discussed, in light of the observations in DarkSide-50. Requirements for future experiments to improve the sensitivity are also discussed, with special attention given to potential background sources.
