Neutrino Backgrounds to Dark Matter Searches and Directionality

Abstract

Neutrino-nucleus coherent scattering cross sections can be as large as 10[superscript −39] cm[superscript 2], while current dark matter experiments have sensitivities to WIMP coherent scattering cross sections several orders of magnitude smaller. With large target masses and few κeV recoil energy detection thresholds, coherent scattering of solar neutrinos becomes an irreducible background. Directional dark matter detection can discriminate against such backgrounds in a second observable: nuclear recoil angle. The motion of our solar system around the galactic center should produce an apparent dark matter wind. With this signal, directional detection of dark matter can provide an unambiguous observation of dark matter interactions even in the presence of backgrounds, from neutrinos and other sources. The DM-TPC collaboration and others are developing recoil direction-sensitive dark matter detectors with very promising results.