17 research outputs found
Sensitivity to Z-prime and non-standard neutrino interactions from ultra-low threshold neutrino-nucleus coherent scattering
We discuss prospects for probing Z-prime and non-standard neutrino
interactions using neutrino-nucleus coherent scattering with ultra-low energy
(~ 10 eV) threshold Si and Ge detectors. The analysis is performed in the
context of a specific and contemporary reactor-based experimental proposal,
developed in cooperation with the Nuclear Science Center at Texas A&M
University, and referencing available technology based upon economical and
scalable detector arrays. For expected exposures, we show that sensitivity to
the Z-prime mass is on the order of several TeV, and is complementary to the
LHC search with low mass detectors in the near term. This technology is also
shown to provide sensitivity to the neutrino magnetic moment, at a level that
surpasses terrestrial limits, and is competitive with more stringent
astrophysical bounds. We demonstrate the benefits of combining silicon and
germanium detectors for distinguishing between classes of models of new
physics, and for suppressing correlated systematic uncertainties.Comment: As published in PRD; 13 pages, 7 figure
Sensitivity to oscillation with a sterile fourth generation neutrino from ultralow threshold neutrino-nucleus coherent scattering
We discuss prospects for probing short-range sterile neutrino oscillation
using neutrino-nucleus coherent scattering with ultra-low energy ( eV
- 100 eV) recoil threshold cryogenic Ge detectors. The analysis is performed in
the context of a specific and contemporary reactor-based experimental proposal,
developed in cooperation with the Nuclear Science Center at Texas A\&M
University, and references developing technology based upon economical and
scalable detector arrays. The baseline of the experiment is substantially
shorter than existing measurements, as near as about 2 meters from the reactor
core, and is moreover variable, extending continuously up to a range of about
10 meters. This proximity and variety combine to provide extraordinary
sensitivity to a wide spectrum of oscillation scales, while facilitating the
tidy cancellation of leading systematic uncertainties in the reactor source and
environment. With 100~eV sensitivity, for exposures on the order of 200
kgy, we project an estimated sensitivity to first/fourth neutrino
oscillation with a mass gap at an amplitude
, or at unit
amplitude. Larger exposures, around 5,000 kgy, together with 10 eV
sensitivity are capable of probing more than an additional order of magnitude
in amplitude.Comment: 4 figures, PRD version, New author added, analysis updated with stat.
estimates based on new measurements and simulation
A Stress Induced Source of Phonon Bursts and Quasiparticle Poisoning
The performance of superconducting qubits is degraded by a poorly
characterized set of energy sources breaking the Cooper pairs responsible for
superconductivity, creating a condition often called "quasiparticle poisoning."
Recently, a superconductor with one of the lowest average quasiparticle
densities ever measured exhibited quasiparticles primarily produced in bursts
which decreased in rate with time after cooldown. Similarly, several cryogenic
calorimeters used to search for dark matter have also observed an unknown
source of low-energy phonon bursts that decrease in rate with time after
cooldown. Here, we show that a silicon crystal glued to its holder exhibits a
rate of low-energy phonon events that is more than two orders of magnitude
larger than in a functionally identical crystal suspended from its holder in a
low-stress state. The excess phonon event rate in the glued crystal decreases
with time since cooldown, consistent with a source of phonon bursts which
contributes to quasiparticle poisoning in quantum circuits and the low-energy
events observed in cryogenic calorimeters. We argue that relaxation of
thermally induced stress between the glue and crystal is the source of these
events, and conclude that stress relaxation contributes to quasiparticle
poisoning in superconducting qubits and the athermal phonon background in a
broad class of rare-event searches.Comment: 13 pages, 6 figures. W. A. Page and R. K. Romani contributed equally
to this work. Correspondence should be addressed to R. K. Roman
Demonstration of surface electron rejection with interleaved germanium detectors for dark matter searches
The following article appeared in Applied Physics Letters 103.16 (2013): 164105 and may be found at http://scitation.aip.org/content/aip/journal/apl/100/26/10.1063/1.4729825The SuperCDMS experiment in the Soudan Underground Laboratory searches for dark matter with a 9-kg array of cryogenic germanium detectors. Symmetric sensors on opposite sides measure both charge and phonons from each particle interaction, providing excellent discrimination between electron and nuclear recoils, and between surface and interior events. Surface event rejection capabilities were tested with two 210 Pb sources producing ∼130 beta decays/hr. In ∼800 live hours, no events leaked into the 8–115 keV signal region, giving upper limit leakage fraction 1.7 × 10−5 at 90% C.L., corresponding to < 0.6 surface event background in the future 200-kg SuperCDMS SNOLAB experiment.This work is supported in part by the National Science Foundation (Grant Nos. AST-9978911, NSF-0847342, PHY-1102795,NSF-1151869, PHY-0542066, PHY-0503729, PHY-0503629, PHY-0503641, PHY-0504224, PHY-0705052,PHY-0801708, PHY-0801712, PHY-0802575, PHY-0847342, PHY-0855299, PHY-0855525, and PHY-1205898), by the Department of Energy (Contract Nos. DE-AC03-76SF00098, DE-FG02-92ER40701, DE-FG02-94ER40823,DE-FG03-90ER40569, DE-FG03-91ER40618, and DESC0004022),by NSERC Canada (Grant Nos. SAPIN 341314 and SAPPJ 386399), and by MULTIDARK CSD2009-00064 and FPA2012-34694. Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359, while SLAC is operated under Contract No. DE-AC02-76SF00515 with the United States Department of
Energy