Fitting the annual modulation in DAMA with neutrons from muons and neutrinos

TL;DR

This paper proposes that neutrons produced by muons and neutrinos interacting with surrounding material could explain the annual modulation signal observed by DAMA, challenging the dark matter interpretation.

Contribution

It introduces a neutron-based model for DAMA's modulation signal, incorporating muon and neutrino interactions, offering an alternative to dark matter explanations.

Findings

Neutron production from muons and neutrinos can mimic DAMA's modulation signal.

Adding neutrino contributions shifts the phase of the combined neutron signal.

Current data fits both dark matter and neutron models equally well.

Abstract

The DAMA/LIBRA experiment searches for evidence of Dark Matter scattering off nuclei. Data from DAMA show 9.2 sigma evidence for an annual modulation, consistent with Dark Matter having a cross section around 2x10^(-40) cm^2. However this is excluded by other Direct Detection experiments. We propose an alternative source of annual modulation in the form of neutrons, which have been liberated from material surrounding the detector by a combination of 8B solar neutrinos and atmospheric muons. The phase of the muon modulation lags 30 days behind the data, however we show that adding the modulated neutrino component shifts the phase of the combined signal forward. In addition we estimate that neutrinos and muons need around 1000 m^3 of scattering material in order to generate enough neutrons to constitute the signal. With current data our model gives as good a fit as Dark Matter and we discuss prospects for future experiments to discriminate between the two.