http://arxiv.org/abs/1804.01231
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 to lower the recoil energy threshold to 1\,keV electron equivalent from 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. The canonical spin-independent case is disfavored by the new data, with best fit points of a DM mass of $\sim 8\,$GeV, disfavored by $5.1\,\sigma$, or a mass of $\sim 53\,$GeV, disfavored by $3.2\,\sigma$. Allowing for isospin violating interactions, we find new best fit regions for spin-independent scattering with suppressed effective couplings to iodine for DM masses of $\sim 10\,$GeV or $\sim 45\,$GeV.
S. Baum, K. Freese and C. Kelso
Thu, 5 Apr 18
30/50
Comments: 8 pages, 3 figures