Dark Matter implications of DAMA/LIBRA-phase2 results

Document Type

Article

Publication Date

2-10-2019

Abstract

Recently, the DAMA/LIBRA collaboration released updated results from their search for the annual modulation signal from Dark Matter (DM) scattering in the detector. Besides approximately doubling the exposure of the DAMA/LIBRA data set, the updated photomultiplier tubes of the experiment allow a lower recoil energy threshold of 1 keV electron equivalent compared to the previous threshold of 2 keV electron equivalent. We study the compatibility of the observed modulation signal with DM scattering. Due to a conspiracy of multiple effects, the new data at low recoil energies is very powerful for testing the DM hypothesis. We find that canonical (isospin conserving) spin-independent DM-nucleon interactions are no longer a good fit to the observed modulation signal in the standard halo model. The canonical spin-independent case is disfavored by the new data, with best fit points of a DM mass of ∼8GeV, disfavored by 5.2σ or a mass of ∼54GeV, disfavored by 2.5σ. Allowing for isospin violating spin independent interactions, we find a region with a good fit to the data with suppressed effective couplings to iodine for DM masses of ∼10GeV. We also consider spin-dependent DM-nucleon interactions, which yield good fits for similar DM masses of ∼10GeV or ∼45GeV.

Publication Title

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

Volume

789

First Page

262

Last Page

269

Digital Object Identifier (DOI)

10.1016/j.physletb.2018.12.036

ISSN

03702693

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