Jingke Xu
(Princeton)
Searches for dark matter with radio-pure argon and NaI(Tl)
Much progress has been made in the development of sensitive experiments for direct detection of dark matter. On the one hand, experiments using Xe and Ge have set stringent limits on the WIMP dark matter parameters based on null observations. The dark matter searches with argon, although coming late, have the potential to yield competitive sensitivity at the multi-ton scale. I will talk about the discovery of underground argon with low-39Ar radioactivity, the background control methods of the DarkSide experiment, and the first physical result from the 1422 kg*d atmospheric run of DarkSide-50. On the other hand, a few other experiments have observed possible evidences for dark matter interactions; particularly, the 9.3 sigma-significance DAMA/LIBRA modulation in NaI(Tl) is yet to be explained. Due to the large uncertainties in current WIMP models, an unambiguous test of DAMA/LIBRA can only be obtained using NaI(Tl), independent of any WIMP models. I will talk about the SABRE effort to develop ultra-high purity NaI(Tl) crystal detectors, to study the NaI(Tl) scintillation properties under nuclear recoils, and to design a definitive experiment.