CRESST is one of the dark matter direct detection experiments seeing an excess which may be interpreted as a signal of a fairly light (order 10 GeV) dark matter particle. Or it was... This week they posted a new paper reporting on new data collected last year with an upgraded detector. Farewell CRESST signal, welcome CRESST limits:
previous CRESST excess: M1 and M2 in the plot. Of course, these regions have never been taken at face value because they are excluded by orders of magnitude by the LUX, Xenon, and CDMS experiments. Nevertheless, the excess was pointing to similar dark matter mass as the signals reported DAMA, CoGeNT, and CDMS-Si (other color stains), which prompted many to speculate a common origin of all these anomalies. Now the excess is gone. Instead, CRESST emerges as an interesting player in the race toward the neutrino wall. Their target material - CaWO4 crystals - contains oxygen nuclei which, due their small masses, are well suited for detecting light dark matter. The kink in the limits curve near 5 GeV is the point below which dark-matter-induced recoil events would be dominated by scattering on oxygen. Currently, CRESST has world's best limits for dark matter masses between 2 and 3 GeV, beating DAMIC (not shown in the plot) and CDMSlite (dashed green line).