Readout strategies for directional dark matter detection beyond the neutrino background
Author(s)O’Hare, Ciaran A. J.; Green, Anne M.; Billard, Julien; Figueroa-Feliciano, Enectali; Strigari, Louis E.
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The search for weakly interacting massive particles (WIMPs) by direct detection faces an encroaching background due to coherent neutrino-nucleus scattering. As the sensitivity of these experiments improves, the question of how to best distinguish a dark matter signal from neutrinos will become increasingly important. A proposed method of overcoming this so-called “neutrino floor” is to utilize the directional signature that both neutrino- and dark-matter-induced recoils possess. We show that directional experiments can indeed probe WIMP-nucleon cross sections below the neutrino floor with little loss in sensitivity due to the neutrino background. In particular we find at low WIMP masses (around 6 GeV) the discovery limits for directional detectors penetrate below the nondirectional limit by several orders of magnitude. For high WIMP masses (around 100 GeV), the nondirectional limit is overcome by a factor of a few. Furthermore we show that even for directional detectors which can only measure one- or two-dimensional projections of the three-dimensional recoil track, the discovery potential is only reduced by a factor of 3 at most. We also demonstrate that while the experimental limitations of directional detectors, such as sense recognition and finite angular resolution, have a detrimental effect on the discovery limits, it is still possible to overcome the ultimate neutrino background faced by nondirectional detectors.
DepartmentMassachusetts Institute of Technology. Department of Physics
Physical Review D
American Physical Society
O’Hare, Ciaran A. J., Anne M. Green, Julien Billard, Enectali Figueroa-Feliciano, and Louis E. Strigari. "Readout strategies for directional dark matter detection beyond the neutrino background." Phys. Rev. D 92, 063518 (September 2015). © 2015 American Physical Society
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