LABORATORI NAZIONALI DI FRASCATI
Speaker: Dinesh Loomba (New Mexico Univ.)
The WIMP direction at Earth undergoes a diurnal modulation that, if detected, would provide one of the most powerful and unambiguous signatures for the discovery of dark matter. Experimental efforts and ideas aimed at detecting this signature have greatly expanded in the last decade, which also saw significant technical progress overcoming a number of challenges. Despite this, the gap in limit-setting sensitivity between directional and non-directional searches has widened. Sensitivity to unexplored WIMP parameter space is, perhaps, the biggest challenge facing the directional community. In this regard, the recent prediction of an irreducible background from solar neutrinos has provided a needed impetus, leading to a resurgence in the field. Directional sensitivity provides the most robust path beyond this so called ‘neutrino-floor’.
After briefly motivating the case for directionality I will focus on the experimental work in directionality by my group at UNM. Here I will begin with our work on the DRIFT experiment, which pioneered the use of negative-ion TPCs for directional DM searches. I will also describe R&D on improving directional and discrimination sensitivity with micro-patterned gas detectors. I will conclude with some new ideas that could lead to a simple, cheap and scalable path to the large volumes needed for future directional DM experiments.