LUX-ZEPLIN

Abstract:

The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118  kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12  eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6  eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16  keV/c^{2}. These are the most stringent constraints to date for these interactions.

Abstract:

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5  kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}  cm^{2} (σ_{p}=5×10^{-40}  cm^{2}) at 35  GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Abstract:

The X-ray luminescence and scintillation properties of undoped ZnTe crystal were investigated as function of temperature down to T<10 K. The luminescence of ZnTe is quenched at room temperature, but below 150 K the crystal exhibits emission at 575 nm with characteristic recombination decay kinetics. The emission is attributed to the radiative annihilation of electrons captured at the shallow levels of impurities or defects with holes trapped by Zn vacancies. The temperature dependence of scintillation light output of ZnTe was studied. It was found that at excitation with α-particles the light output of undoped ZnTe is 117±20% of a reference CaWO4 crystal measured under the same experimental conditions. It is concluded that undoped zinc telluride is a promising scintillator for cryogenic application, particularly for the cryogenic search for neutrinoless double beta decay (0νDBD) of ¹³⁰Te.