The Electronics and Data Acquisition System of the DarkSide Dark Matter Search

It is generally inferred from astronomical measurements that Dark Matter (DM) comprises approximately 27\% of the energy-density of the universe. If DM is a subatomic particle, a possible candidate is a Weakly Interacting Massive Particle (WIMP), and the DarkSide-50 (DS) experiment is a direct search for evidence of WIMP-nuclear collisions. DS is located underground at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, and consists of three active, embedded components; an outer water veto (CTF), a liquid scintillator veto (LSV), and a liquid argon (LAr) time projection chamber (TPC). This paper describes the data acquisition and electronic systems of the DS detectors, designed to detect the residual ionization from such collisions

Search for Lepton-Universality Violation in B^{+}→K^{+}ℓ^{+}ℓ^{-} Decays.

A measurement of the ratio of branching fractions of the decays B^{+}→K^{+}μ^{+}μ^{-} and B^{+}→K^{+}e^{+}e^{-} is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0  fb^{-1} recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1<q^{2}<6.0  GeV^{2}/c^{4} the ratio of branching fractions is measured to be R_{K}=0.846_{-0.054}^{+0.060}_{-0.014}^{+0.016}, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of R_{K} to date and is compatible with the standard model at the level of 2.5 standard deviations

Measurement of the Z y production cross section in pp collisions at 8 TeV and search for anomalous triple gauge boson couplings

The cross section for the production of Z &#947; in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb &#8722;1 . Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZ &#947; and Z &#947;&#947; are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson

Stepwise expansions of C-4 biomass and enhanced seasonal precipitation and regional aridity during the Quaternary on the southern Chinese Loess Plateau

The expansion of C-4 plants is one of the most prominent vegetation changes in the global ecosystem during the Cenozoic Era. Although C-4 plant expansions in the latest Miocene have been widely reported, factors driving the expansions are still in debate, and the details of vegetation changes during the Quaternary have not been well studied. Here we present high-resolution carbon isotope time series of both organic matter and bulk carbonates, covering the past 2.58 Ma, derived from the loess-soil successions on the southern Chinese Loess Plateau. The organic matter delta C-13 values indicate stepwise C-4 plant expansions initiated at similar to 1.6 and at similar to 0.43 Ma, respectively. We conclude that such tectonic time scale C-4 plant expansions are controlled by enhanced seasonality of precipitation (relatively more precipitation in the warm growing season) as well as regional aridity, and this long-term fluctuation superimposes on the orbital scale variations of C-4 plants, while the latter appears phase-locked with cyclical changes of summer monsoon circulations.</p

Effect of aridification on carbon isotopic variation and ecologic evolution at 5.3 Ma in the Asian interior

The Cenozoic era is marked by dramatic climatic and ecological changes. The timing of the emergence and the subsequent expansions of C-4 grasses are prominent biological events on Earth. In China, thick Cenozoic deposits in the Tarim and Junggar Basins, which are located in the Asian interior, provide important geological archives for studying paleoenvironmental changes. Here we use carbon isotope compositions of organic matter to reconstruct the history of ecologic evolution during the late Cenozoic in the Tarim and Junggar Basins. The results show that there is a shift to slightly higher delta C-13 values at 5.3 Ma indicating a change in terrestrial ecosystems in the Asian interior driven by an increased regional aridity rather than decreasing atmospheric pCO(2) levels. The weakened water vapor transportation related to the retreat of Paratethys Ocean and the enhanced rain shadow effect of mountain uplift during the latest Miocene mostly triggered this event.</p

Day-Night Differences, Seasonal Variations andSource Apportionment of PM10-Bound PAHs overXi’an, Northwest China

Day-night PM10-bound PAHs were studied at an urban site of Xi’an from 20 December 2006 to 28 October 2007. The annual mean concentration of nighttime PAHs (285.0 ng m−3) was higher than that in daytime (239.4 ng m−3). A significant difference of PAH concentrations between daytime and nighttime was found in autumn with a coefficient of divergence (CD) of 0.23 (significant level 0.2). However, no distinct difference was observed in other seasons (with CD values < 0.2), although the difference of PAHs partition capacity in PM10 between daytime and nighttime was significant in the four seasons. Remarkable seasonal variations were observed in the total PAH levels, with a highest mean concentration of 344.6 ng m−3 in winter and a lowest mean concentration of 177 ng m−3 in summer. Positive matrix factorization results revealed that residential emission for heating is the major contributor of the elevated PAH levels in winter, accounting for 49% of the total PAH levels. The coal combustion including industrial and residential usage, contributed over 40% of the PAH emissions in PM10 of Xi’an during the one-year sampling period. These results can provide guidance for taking measures in reducing PAHs levels in the air