Work

Boosted dark particles and the LZ nuclear recoil event

Year: 2026
Type: preprint
Abstract: The LZ experiment reported one anomalous event with nuclear recoil energy of 248 keV. Galactic halo dark matter (DM) cannot produce such a large energy unless heavier than 74 GeV, and heavy DM with spin-independent interactions would have produced unseen recoils at lower energy. Inelastic DM has been proposed as a way out. We consider, instead, an elastic collision of a dark sector particle with a momentum of at least 123~MeV and mass in the range 1-74 GeV as deuteron break-up in SNO disfavors sub-GeV masses. The absence of accompanying lower-energy recoils favours interactions whose rate grows with the momentum transfer, such as a pseudoscalar-pseudoscalar nucleon operator. This implies no leading-order signal in argon, an annual modulation below 1 %, and recoils in spinful light nuclei where inelastic halo DM gives nothing.
Language: English
Open Access status: green
OpenAlex ID: W7212037578
Cites: 62
Cited by: 28
Related to: 10