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Niklas Zimmermann

Publications and source records attributed to Niklas Zimmermann.

2 recordsLinked to original sources

DAMA/LIBRA dark matter signal: a global analysis

The annual modulation reported by the DAMA/LIBRA collaboration remains in tension with the null results of other direct-detection experiments. We investigate the compatibility of DAMA/LIBRA with LZ, PICO-60 and CDMSlite within a generalized non-relativistic effective field theory (EFT) framework. In addition to the EFT operator expansion we investigate additional modifications to the standard WIMP picture, including inelastic scattering, variations in the NaI quenching factors, and a rescaling of the dark-matter velocity dispersion. We perform a Markov chain Monte Carlo analysis in this extended model space, using two alternative approaches to the likelihood function describing the DAMA/LIBRA data. Both approaches result in strong discrepancy between the data from DAMA/LIBRA and other experiments. We conclude that the extended model space considered here cannot accommodate the DAMA/LIBRA signal while remaining consistent with the non-observation of dark matter in other experiments.

hep-ph↗

Cosmic ray boosted dark matter with momentum dependent interactions can explain the LZ 248 keV event

The LZ experiment has recently reported an observation of a single event with characteristics of a nuclear recoil at a high recoil energy of 248 keV, where no background events are expected. We show that such nuclear recoil event could be caused by high velocity dark matter particles originating from interactions with energetic cosmic rays. We analyze the expected recoil spectrum due to cosmic ray boosted dark matter within the non-relativistic effective theory formalism, and show that momentum-dependent operators, such as $\mathcal{O}_6$ and $\mathcal{O}_{10}$, can produce a spectrum that peaks at the observed energy.

hep-ph↗