Diamond detectors for direct detection of sub-GeV dark matter

Abstract

We propose to use high-purity lab-grown diamond for the detection of sub-GeV dark matter. Diamond targets can be sensitive to both nuclear and electron recoils from dark matter scattering in the MeV and above mass range, as well as to absorption processes of dark matter with masses between sub-eV to 10's of eV. Compared to other proposed semiconducting targets such as germanium and silicon, diamond detectors can probe lower dark matter masses via nuclear recoils due to the lightness of the carbon nucleus. The expected reach for electron recoils is comparable to that of germanium and silicon, with the advantage that dark counts are expected to be under better control. Via absorption processes, unconstrained QCD axion parameter space can be successfully probed in diamond for masses of order 10 eV, further demonstrating the power of our approach.

Multiphonon excitations from dark matter scattering in crystals

“…3), and moreover it does not rely on the validity of Eq. (20). The size of the band is larger in GaAs and Ge because of the lower sound speeds and ω cut (Tab.…”

“…The very high sound speed of diamond then explains why this material maintains sensitivity to the single acoustic mode for most of the mass range, even for a threshold as high as ∼ 10 meV. (See [20] for a detailed study of diamond as a dark matter detector. )…”

Multichannel direct detection of light dark matter: Target comparison

“…Toward this goal, in Secs. III and IV, we carry out a detailed comparison of target materials, focusing on two benchmark DM scenarios to illustrate how arXiv:1910.10716v1 [hep-ph] 23 Oct 2019 to optimize target choice for the best sensitivity. Our study covers a total of 24 crystal materials, whose key properties that determine sensitivity to DM scattering are summarized in Table I…”

Small scale direct dark matter search experiments

“…In the SnowBall proposal supercooled water is used so that an incoming particle triggers crystallization of purified water using a camera for image acquisition; this has been tested with neutrons at −20 o [59]. Lab-grown diamond crystals as target outfitted with cryogenic phonon and charge readout could be sensitive to dark matter scattering of very low mass candidates [60]. In the so-called paleo-detectors, persistent traces left by dark matter interaction in ancient minerals could be searched for profiting from a large integration time [61].…”