LUX-ZEPLIN (LZ) is a next generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. ...Using a two-phase xenon detector with an active mass of 7~tonnes, LZ will search primarily for low-energy interactions with Weakly Interacting Massive Particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000~live day run using a 5.6~tonne fiducial mass, LZ is projected to exclude at 90\% confidence level spin-independent WIMP-nucleon cross sections above \(1.4 \times 10^{-48}\)~cm\(^{2}\) for a 40~\(\mathrm{GeV}/c^{2}\) mass WIMP. Additionally, a \(5\sigma\) discovery potential is projected reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of \(2.3 \times 10^{-43}\)~cm\(^{2}\) (\(7.1 \times 10^{-42}\)~cm\(^{2}\)) for a 40~\(\mathrm{GeV}/c^{2}\) mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020.
The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and ...proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of \(^{238}\)U\(_{e}\)~\(<\)1.6~mBq/kg, \(^{238}\)U\(_{l}\)~\(<\)0.09~mBq/kg, \(^{232}\)Th\(_{e}\)~\(=0.28\pm 0.03\)~mBq/kg, \(^{232}\)Th\(_{l}\)~\(=0.25\pm 0.02\)~mBq/kg, \(^{40}\)K~\(<\)0.54~mBq/kg, and \(^{60}\)Co~\(<\)0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of \(0.160\pm0.001\)(stat)\(\pm0.030\)(sys) counts.
In this Technical Design Report (TDR) we describe the LZ detector to be built at the Sanford Underground Research Facility (SURF). The LZ dark matter experiment is designed to achieve sensitivity to ...a WIMP-nucleon spin-independent cross section of three times ten to the negative forty-eighth square centimeters.
Rolls, streets, waves, and more Young, George S; Kristovich, David A R; Hjemfelt, Mark R ...
Bulletin of the American Meteorological Society,
07/2002, Volume:
83, Issue:
7
Journal Article
Peer reviewed
The atmospheric boundary layer is home to a number of horizontally elongated quasi-two-dimensional phenomena including cloud streets, roll vortices, thermal waves, and surface layer streaks. These ...phenomena, their dynamics, and their interactions are explored via a review of the literature.
