We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35 × 10 4 kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c −2 , WIMP-nucleon spin-independent cross sections above 2.2 × 10 −46 cm 2 are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1 × 10 −46 cm 2 at 50 GeV c −2 .

The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for the first time in the underground laboratory in February 2013. We report results of the first WIMP search dataset, taken during the period April to August 2013, presenting the analysis of 85.3 live-days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10 −46 cm 2 at a WIMP mass of 33 GeV/c 2 . We find that the LUX data are in disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.PACS numbers: 95.35.+d, 95.55.Vj

We report results of a search for light (10 GeV) particle dark matter with the XENON10 detector. The event trigger was sensitive to a single electron, with the analysis threshold of 5 electrons corresponding to 1.4 keV nuclear recoil energy. Considering spin-independent dark matter-nucleon scattering, we exclude cross sections n>7×10-42 cm2, for a dark matter particle mass m=7 GeV. We find that our data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.

The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and the ionization produced by radiation in pure liquid xenon to discriminate signal from background down to 4.5 keV nuclear-recoil energy. A blind analysis of 58.6 live days of data, acquired between October 6, 2006, and February 14, 2007, and using a fiducial mass of 5.4 kg, excludes previously unexplored parameter space, setting a new 90% C.L. upper limit for the WIMP-nucleon spin-independent cross section of 8.8x10(-44) cm2 for a WIMP mass of 100 GeV/c2, and 4.5x10(-44) cm2 for a WIMP mass of 30 GeV/c2. This result further constrains predictions of supersymmetric models.

Check any evidence for WIMP signals using experiments with complementary technologies, and also with an experiment using the original target material, but having better sensitivity StudyIf a signal is confirmed, study it with multiple technologies in order to extract maximal information about WIMP properties R&DMaintain a robust detector R&D program on technologies that can enable discovery, confirmation and study of WIMPs.

Borexino, a large volume detector for low energy neutrino spectroscopy, is currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. The main goal of the experiment is the real-time measurement of sub MeV solar neutrinos, and particularly of the mono energetic (862 keV) Be7 electron capture neutrinos, via neutrino-electron scattering in an ultra-pure liquid scintillator. This paper is mostly devoted to the description of the detector structure, the photomultipliers, the electronics, and the trigger and calibration systems. The real performance of the detector, which always meets, and sometimes exceeds, design expectations, is also shown. Some important aspects of the Borexino project, i.e. the fluid handling plants, the purification techniques and the filling procedures, are not covered in this paper and are, or will be, published elsewhere (see Introduction and Bibliography)

We report the direct measurement of the 7 Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV 7 Be neutrinos is 49±3stat±4syst counts/(day·100 ton). The hypothesis of no oscillation for 7 Be solar neutrinos is inconsistent with our measurement at the 4σ C.L.. Our result is the first direct measurement of the survival probability for solar νe in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of 7 Be, pp, and CNO solar νe, and the limit on the magnetic moment of neutrinos.PACS numbers: 13.35. Hb, 14.60.St, 26.65.+t, 95.55.Vj, 29.40.Mc Neutrino oscillations [1] are the established mechanism to explain the solar neutrino problem, which originated from observations in radiochemical experiments with a sub-MeV threshold [2,3] and from real time observation of high energy neutrinos [4,5]. Neutrino oscillations were also observed in atmospheric neutrinos [4] and have been confirmed with observation of reactorν e [6]. Borexino is the first experiment to report a real-time observation arXiv:0805.3843v2 [astro-ph]

Development of large mass detectors for low-energy neutrinos and dark matter may allow supernova detection via neutrino-nucleus elastic scattering. An elastic-scattering detector could observe a few, or more, events per ton for a galactic supernova at 10 kpc (3.1 × 10 20 m). This large yield, a factor of at least 20 greater than that for existing light-water detectors, arises because of the very large coherent cross section and the sensitivity to all flavors of neutrinos and antineutrinos. An elastic scattering detector can provide important information on the flux and spectrum of νµ and ντ from supernovae. We consider many detectors and a range of target materials from 4 He to 208 Pb. Monte Carlo simulations of low-energy backgrounds are presented for the liquid-neon-based Cryogenic Low Energy Astrophysics with Noble gases (CLEAN) detector. The simulated background is much smaller than the expected signal from a galactic supernova.