Are DAMA-region NaI events nuclear or electron recoils?
In plain words
A dark matter particle would mostly knock a nucleus, while radioactivity mostly knocks electrons. A cooled sodium iodide detector that measures both heat and light can tell these apart.
Precise statement
Conventional NaI(Tl) scintillators cannot discriminate nuclear from electron recoils at 1-6 keVee. A cryogenic NaI scintillating calorimeter (COSINUS at LNGS) reads phonon and scintillation channels, giving recoil-type discrimination event by event. The question is the composition of the 1-6 keVee rate in NaI and whether any modulating component is nuclear-recoil-like.
What would settle it
A COSINUS-type measurement with nuclear-electron recoil discrimination and enough exposure to test the DAMA rate and modulation in the nuclear-recoil band.
Status in the literature
Unverified note
COSINUS-1pi Run 1 with eight cryogenic NaI modules at LNGS was planned to start data taking in 2026 (Commun. Phys. 9, 213, 2026); no result yet.
Related problems
- Special case of What produces the DAMA/LIBRA annual modulation?