DAMA annual modulation is not due to electron recoils from Plasma/Mirror Dark Matter with Kinetic Mixing

TL;DR

This paper tests the plasma dark matter model as an explanation for DAMA's observed annual modulation and finds strong statistical evidence against it being the cause.

Contribution

It provides a rigorous statistical analysis that rules out plasma dark matter with kinetic mixing as the source of DAMA's annual modulation.

Findings

Plasma dark matter model is rejected at over 7σ confidence level.

DAMA's annual modulation cannot be explained by plasma or mirror dark matter.

The analysis constrains dark matter models involving electron recoils from plasma interactions.

Abstract

If dark matter is composed of new fundamental particles, Earth's orbital motion around the Sun may induce an annual modulation in the rate at which these particles interact in a terrestrial detector. The DAMA collaboration has identified at a 12$\sigma$ confidence level such an annual modulation in their event rate. One previously proposed explanation is `plasma dark matter' (e.g. mirror dark matter) which would have electron recoils in the detector from interactions via kinetic mixing. We perform a chi-squared goodness of fit test of this plasma dark matter model to DAMA/LIBRA modulation amplitude which rejects the hypothesis of plasma dark matter as an explanation of this data at greater than 7$\sigma$.