DAMA/LIBRA annual modulation and axion quark nugget dark matter model

Abstract

The DAMA/LIBRA experiment shows $9.5 \sigma$ evidence for an annual modulation in the $(1-6)~ {\rm keV}$ energy range, strongly suggesting that the observed modulation has the dark matter origin. However, the conventional interpretation in terms of WIMP-nucleon interaction is excluded by other experiments. We propose an alternative source of modulation in the form of neutrons, which have been liberated from surrounding material. Our computations are based on the so-called Axion Quark Nugget (AQN) dark matter model, which was originally invented long ago to explain the similarity between the dark and visible cosmological matter densities, i.e. $ \Omega_{\rm dark} \sim \Omega_{\rm visible}$. In our proposal the annual modulation is shown to be generated in keV energy range which is consistent with DL observation in $(1-6)~ {\rm keV}$ range. This keV energy scale in our proposal is mostly determined by spectral properties of the neutrinos emitted by the AQN dark matter particles, while the absence of the modulation with energies above 6 keV is explained by a sharp cutoff in the neutrino's energy spectrum at $\sim 15$ MeV. This proposal can be directly tested by COSINE-100, ANAIS-112, CYGNO and other similar experiments. It can be also tested by studying the correlations between the signals from these experiments and the signatures from drastically different detectors designed for studies of the infrasonic or seismic events using such instruments as Distributed Acoustic Sensing (DAS).