Magnetic Inelastic Dark Matter

TL;DR

This paper investigates inelastic dark matter models exploiting iodine's large mass and magnetic moment, proposing magnetic interactions to reconcile DAMA's signal with other experiments and predicting detectable signals in xenon detectors.

Contribution

It introduces novel inelastic dark matter models that incorporate iodine's magnetic moment, expanding the interaction types beyond electric couplings and analyzing their experimental implications.

Findings

XENON100 and CRESST should observe signals, albeit suppressed.

KIMS is expected to see a modulated signal comparable to DAMA.

Prompt de-excitation produces detectable photons, affecting event selection.

Abstract

Iodine is distinguished from other elements used in dark matter direct detection experiments both by its large mass as well as its large magnetic moment. Inelastic dark matter utilizes the large mass of iodine to allay tensions between the DAMA annual modulation signature and the null results from other experiments. We explore models of inelastic dark matter that also take advantage of the second distinct property of iodine, namely its large magnetic moment. In such models the couplings are augmented by magnetic, rather than merely electric, interactions. These models provide simple examples where the DAMA signal is compatible with all existing limits. We consider dipole moments for the WIMP, through conventional magnetism as well as "dark" magnetism, including both magnetic-magnetic and magnetic-electric scattering. We find XENON100 and CRESST should generically see a signal, although suppressed compared with electric inelastic dark matter models, while KIMS should see a modulated signal comparable to or larger than that of DAMA. In a large portion of parameter space, de-excitation occurs promptly, producing a ~ 100 keV photon inside large xenon experiments alongside the nuclear recoil. This effect could be searched for, but if not properly considered may cause nuclear recoil events to fail standard cuts.