Searches for light Dark Matter with Spherical Proportional Counters

Abstract: Elucidating the nature of dark matter is a key priority that would involve discovering new fundamental physics and is essential for understanding the structure and evolution of the universe. Despite the decades-long ever-more-sensitive searches, the particle content of dark matter remains elusive. Direct searches for dark matter candidates, to-date, focused mainly on candidates in the 10 GeV to 1 TeV, however, more recently lighter candidates with sub-GeV mass have been brought to the spotlight. This is an experimentally challenging mass region, which remains largely uncharted. The spherical proportional counter is a new type of gaseous detector which exhibits several features that make it ideally suited for the exploration of this mass range. In this article the invention and development of the spherical proportional counter are presented, its applications in the search for particle dark matter and beyond are reviewed, and possible future directions are discussed.