Contamination of Dark Matter Experiments from Atmospheric Magnetic Dipoles

TL;DR

This paper investigates whether atmospheric magnetic dipoles, such as sterile neutrinos with magnetic moments, could mimic dark matter signals in direct detection experiments, potentially explaining conflicting experimental results.

Contribution

It introduces a scenario where atmospheric magnetic dipoles could produce signals similar to dark matter, supported by a concrete sterile neutrino model.

Findings

A flux of atmospheric magnetic dipoles can explain signals at DAMA/LIBRA, CDMS/Si, and CoGeNT.

The scenario is consistent with bounds from XENON100 and CDMS/Ge.

A sterile neutrino model with 10-50 MeV mass supports this hypothesis.

Abstract

Dark matter collisions with heavy nuclei (Xe, Ge, Si, Na) may produce recoils observable at direct-search experiments. Given that some of these experiments are yielding conflicting information, however, it is worth asking if physics other than dark matter may produce similar nuclear recoils. We examine under what conditions an atmospherically-produced neutral particle with a relatively large magnetic dipole moment could fake a dark matter signal. We argue that a very definite flux could explain the signals seen at DAMA/LIBRA, CDMS/Si and CoGeNT consistently with the bounds from XENON100 and CDMS/Ge. To explore the plausibility of this scenario, we discuss a concrete model with 10-50 MeV sterile neutrinos that was recently proposed to explain the LSND and MiniBooNE anomalies.