New results on low-mass dark matter and double beta decay of ¹³⁴Xe

Two new results were released on the same day, one from each side of our research program. Both have since been published.

Low-mass dark matter in liquid argon. Sensitivity to low-mass WIMPs with an improved liquid argon ionization response model within the DarkSide program (Phys. Rev. D 113, 123045) combines new measurements from the ReD setup with calibration data from DarkSide-50 and results from the ARIS and SCENE experiments to better constrain how liquid argon responds to nuclear recoils at keV energies. Applying the updated model to DarkSide-50 data yields stronger exclusion limits on low-mass WIMP interactions, and the paper recasts the sensitivity projections for DarkSide-20k.

Double beta decay of ¹³⁴Xe. Search for Double Beta Decays of ¹³⁴Xe with EXO-200 Phase II (Phys. Rev. Lett. 136, 232502) reports no significant signal and sets a world-leading lower limit of 8.7 × 10²³ years (90% C.L.) on the half-life of the neutrinoless mode, along with a threefold improvement over the EXO-200 Phase I constraint on the two-neutrino mode.