Low-Mass WIMP Sensitivity and Statistical Discrimination of Electron and   Nuclear Recoils by Varying Luke-Neganov Phonon Gain in Semiconductor   Detectors
  Amplifying the phonon signal in a semiconductor dark matter detector can be accomplished by operating at high voltage bias and converting the electrostatic potential energy into Luke-Neganov phonons. This amplification method has been validated at up to |E|=40V/cm without producing leakage in CDMSII Ge detectors, allowing sensitivity to a benchmark WIMP with mass = 8GeV and cross section 1.8e-42cm^2 assuming flat electronic recoil backgrounds near threshold. Furthermore, for the first time we show that differences in Luke-Neganov gain for nuclear and electronic recoils can be used to discriminate statistically between low-energy background and a hypothetical WIMP signal by operating at two distinct voltage biases. Specifically, 99% of events have p-value<1e-8 for a simulated 20kg-day experiment with a benchmark WIMP signal with mass =8GeV and cross section =3.3e-41cm^2. 
M. Pyle (1), D. A. Bauer (2), B. Cabrera (1), J. Hall (2), R. W.   Schnee (3), R. Basu Thakur (2,4), S. Yellin (1) ((1) Stan...
astro-ph.IM