Anapole Dark Matter after DAMA/LIBRA-phase2

TL;DR

This paper critically evaluates anapole dark matter as an explanation for DAMA/LIBRA-phase2 annual modulation signals, finding it incompatible with other dark matter search results under standard assumptions.

Contribution

It provides a comprehensive re-analysis of anapole dark matter in light of new experimental data and halo-independent methods, highlighting its limitations as an explanation for DAMA signals.

Findings

Anapole dark matter cannot explain DAMA modulation above 2 keVee with Maxwellian velocity distribution.

It fits DAMA-phase2 data better than isoscalar spin-independent interactions due to magnetic coupling.

Current null results strongly constrain anapole dark matter as a viable explanation.

Abstract

We re-examine the case of anapole dark matter as an explanation for the DAMA annual modulation in light of the DAMA/LIBRA-phase2 results and improved upper limits from other DM searches. If the WIMP velocity distribution is assumed to be a Maxwellian, anapole dark matter is unable to provide an explanation of the DAMA modulation compatible with the other searches. Nevertheless, anapole dark matter provides a better fit to the DAMA-phase2 modulation data than an isoscalar spin-independent interaction, due to its magnetic coupling with sodium targets. A halo-independent analysis shows that explaining the DAMA modulation above 2 keVee in terms of anapole dark matter is basically impossible in face of the other null results, while the DAMA/LIBRA-phase2 modulation measurements below 2 keVee are marginally allowed. We conclude that in light of current measurements, anapole dark matter does not seem to be a viable explanation for the totality of the DAMA modulation.