Conservative boundary conditions for 3D gas dynamics problems

A method is described for 3D-gas dynamics computer simulation in regions of complicated shape by means of nonadjusted rectangular grids providing unified treatment of various problems. Some test problem computation results are given

Linkages between the circulation and distribution of dissolved organic matter in the White Sea, Arctic Ocean

AbstractThe White Sea is a semi-enclosed Arctic marginal sea receiving a significant loading of freshwater (225–231km3yr−1 equaling an annual runoff yield of 2.5m) and dissolved organic matter (DOM) from river run-off. We report discharge weighed values of stable oxygen isotope ratios (δ18O) of −14.0‰ in Northern Dvina river for the period 10 May–12 October 2012. We found a significant linear relationship between salinity (S) and δ18O (δ18O=−17.66±0.58+0.52±0.02×S; R2=0.96, N=162), which indicates a dominant contribution of river water to the freshwater budget and little influence of sea ice formation or melt. No apparent brine additions from sea-ice formation is evident in the White Sea deep waters as seen from a joint analysis of temperature (T), S, δ18O and aCDOM(350) data, confirming previous suggestions about strong tidal induced vertical mixing in winter being the likely source of the deep waters. We investigated properties and distribution of colored dissolved organic matter (CDOM) and dissolved organic carbon (DOC) in the White Sea basin and coastal areas in summer. We found contrasting DOM properties in the inflowing Barents Sea waters and White Sea waters influenced by terrestrial runoff. Values of absorption by CDOM at 350nm (aCDOM(350)) and DOC (exceeding 10m−1 and 550µmoll−1, respectively) in surface waters of the White Sea basin are higher compared to other river-influenced coastal Arctic domains. Linear relationship between S and CDOM absorption, and S and DOC (DOC=959.21±52.99–25.80±1.79×S; R2=0.85; N=154) concentrations suggests conservative mixing of DOM in the White Sea. The strongest linear correlation between CDOM absorption and DOC was found in the ultraviolet (DOC=56.31±2.76+9.13±0.15×aCDOM(254); R2=0.99; N=155), which provides an easy and robust tool to trace DOC using CDOM absorption measurements as well as remote sensing algorithms. Deviations from this linear relationship in surface waters likely indicate contribution from different rivers along the coast of the White Sea. Characteristics of CDOM further indicate that there is limited removal or change in the DOM pool before it exits to the Barents Sea

Measurement of electroweak Z(νν¯)γjj production and limits on anomalous quartic gauge couplings in pp collisions at √s = 13 TeV with the ATLAS detector

The electroweak production of Z(νν¯)γ in association with two jets is studied in a regime with a photon of high transverse momentum above 150 GeV using proton–proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The analysis uses a data sample with an integrated luminosity of 139 fb−1 collected by the ATLAS detector during the 2015–2018 LHC data-taking period. This process is an important probe of the electroweak symmetry breaking mechanism in the Standard Model and is sensitive to quartic gauge boson couplings via vector-boson scattering. The fiducial Z(νν¯)γjj cross section for electroweak production is measured to be 0.77+0.34−0.30 fb and is consistent with the Standard Model prediction. Evidence of electroweak Z(νν¯)γjj production is found with an observed significance of 3.2σ for the background-only hypothesis, compared with an expected significance of 3.7σ. The combination of this result with the previously published ATLAS observation of electroweak Z(νν¯)γjj production yields an observed (expected) signal significance of 6.3σ (6.6σ). Limits on anomalous quartic gauge boson couplings are obtained in the framework of effective field theory with dimension-8 operators

Measurement of electroweak Z(νν) γjj production and limits on anomalous quartic gauge couplings in pp collisions at s√ = 13 TeV with the ATLAS detector

The electroweak production of Z(νν¯¯¯)γ in association with two jets is studied in a regime with a photon of high transverse momentum above 150 GeV using proton–proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The analysis uses a data sample with an integrated luminosity of 139 fb−1 collected by the ATLAS detector during the 2015–2018 LHC data-taking period. This process is an important probe of the electroweak symmetry breaking mechanism in the Standard Model and is sensitive to quartic gauge boson couplings via vector-boson scattering. The fiducial Z(νν¯¯¯)γjj cross section for electroweak production is measured to be 0.77+0.34−0.30 fb and is consistent with the Standard Model prediction. Evidence of electroweak Z(νν¯¯¯)γjj production is found with an observed significance of 3.2σ for the background-only hypothesis, compared with an expected significance of 3.7σ. The combination of this result with the previously published ATLAS observation of electroweak Z(νν¯¯¯)γjj production yields an observed (expected) signal significance of 6.3σ (6.6σ). Limits on anomalous quartic gauge boson couplings are obtained in the framework of effective field theory with dimension-8 operators

Technique for Setting Limits on the Coupling Constants of the Effective Theory from Electroweak ZγZ_\gamma Production at the Conditions of Run-2 of the ATLAS Experiment

Tests for deviation from the Standard Model (SM) are guided by its apparent incompleteness and by pursuit of creation of a more general theory of elementary particles. We search in this study for manifestations of new physics in an indirect way, through changes in interactions of already known particles due to the effects of physics beyond the SM. The non-SM interactions are referred to as anomalous (or anomalous couplings). Electroweak Zγ production is a process sensitive to anomalous quartic bosonic couplings. The phenomenology we apply, the effective field theory, enables a model-independent representation of the sought-for effects of new physics in the form of parametrization of the SM Lagrangian using higher-dimensional operators. Each such operator is preceded by a coefficient, which has the meaning of the theory’s coupling constants. We present here a technique developed to set 1D limits on the values of these coefficients. This technique makes it possible to set for some operators the expected limits that are more stringent than the currently available ones