Muon-induced neutrons do not explain the DAMA data

TL;DR

This study models muon-induced backgrounds in DAMA/LIBRA and finds they cannot account for the observed signal modulation, challenging previous hypotheses that linked muons to the DAMA data.

Contribution

The paper provides an accurate simulation of muon-induced neutrons and demonstrates these backgrounds are insufficient to explain DAMA's observed modulation signal.

Findings

Muon-induced neutron flux is very low in the detector cavern.

Predicted muon-induced counts are less than 0.3% of the DAMA modulation.

Muon backgrounds do not explain the DAMA signal modulation.

Abstract

We present an accurate model of the muon-induced background in the DAMA/LIBRA experiment. Our work challenges proposed mechanisms which seek to explain the observed DAMA signal modulation with muon-induced backgrounds. Muon generation and transport are performed using the MUSIC/MUSUN code, and subsequent interactions in the vicinity of the DAMA detector cavern are simulated with Geant4. We estimate the total muon-induced neutron flux in the detector cavern to be $\Phi_n^\nu = 1.0\times10^{-9}$ cm$^{-2}$ s$^{-1}$. We predict $3.49\times10^{-5}$ counts/day/kg/keV, which accounts for less than $0.3\%$ of the DAMA signal modulation amplitude.