Wanted! Nuclear Data for Dark Matter Astrophysics

Abstract

Astronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elementary particle. Searches for dark matter particles are under way: production at high-energy accelerators, direct detection through dark matter-nucleus scattering, indirect detection through cosmic rays, gamma rays, or effects on stars. Particle dark matter searches rely on observing an excess of events above background, and a lot of controversies have arisen over the origin of observed excesses. With the new high-quality cosmic ray measurements from the AMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in the nuclear physics cross sections for spallation and fragmentation of cosmic rays off interstellar hydrogen and helium. The understanding of direct detection backgrounds is limited by poor knowledge of cosmic ray activation in detector materials, with order of magnitude differences between simulation codes. A scarcity of data on nucleon spin densities blurs the connection between dark matter theory and experiments. What is needed, ideally, are more and better measurements of spallation cross sections relevant to cosmic rays and cosmogenic activation, and data on the nucleon spin densities in nuclei.

Solar and nuclear physics uncertainties in cosmic-ray propagation

“…Hence, in the analysis of CR data, these uncertainties cannot be ignored any longer. In line with recent studies, all calling for more precise nuclear data for CRs [37,48,56,57,65], we therefore stress once more the urgent need for establishing a program of cross-section measurements at the O(100 GeV) energy scale. To conclude, we would like to quote Chen et al 1997 [66] from the Transport Collaboration: "With the shutdown of the LBL Bevalac and the pending closure of the Saclay Saturne accelerators, opportunities for obtaining cross-section measurements relevant to the interpretation of CR data are rapidly dwindling worldwide.…”

Examination of uncertainties in nuclear data for cosmic ray physics with the AMS experiment

“…It also worth stressing that this problem has a direct impact in dark matter searches. My study provides a concrete case study for Gondolo's plea to the nuclear physics community [43]. In summary, nuclear uncertainties are a major limiting factor for further progress in CR propagation.…”

The electroweak sector of the pMSSM in the light of LHC - 8 TeV and other data

“…8 Apart from particle physics and astrophysics related uncertainties, see also ref. [163] for the uncertainty arising out of poor knowledge of cosmic ray activation in detector materials in regard to direct detection backgrounds.…”