The DANSS detector is located directly under the nuclear reactor at the Kalinin nuclear power plant. Such a position ensures about 50 m.w.e. shielding from cosmic rays in the vertical direction; as a ...result, the detector occupies an intermediate position between surface and underground detectors in the shielding from cosmic rays. The sensitive volume of the detector consisting of a 1-m
3
plastic scintillator is surrounded by the multilayer passive shielding and muon veto. The main aim of the DANSS experiment is to measure the antineutrino spectrum at various distances from the source. To this end, the detector is placed on a lifting platform in order to record data at three positions of 10.9, 11.9, and 12.9 m from the reactor core. The detector can reconstruct muon tracks passing through its sensitive volume. The pressure, temperature, and decay coefficients for muons in various regions of the zenith angle
have been determined from the muon data collected during four years using the effective generation level method.
Detection of antineutrino by the reaction of the inverse
β
-decay can be used for an independent monitoring of a nuclear reactor power. DANSS detector is located directly under a commercial WWER-1000 ...reactor and counts up to 5000 antineutrino per day, providing the accuracy of 1.5% in 2 days of the flux measurement. A powerful system of the passive and active shielding in combination with the fine spatial segmentation of the detector allows to diminish the contribution of the background processes to a level, negligible in comparison to the statistical error. The influence of the nuclear fuel composition on the neutrino flux can be accounted for based on the input from the NPP staff.
The angular distribution and differential branching fraction of the decay $B^{0} \to K^{*0} \mu^{+}\mu^{-}$ are studied using a data sample, collected by the LHCb experiment in $pp$ collisions at ...$\sqrt{s}=7\,{\rm TeV}$, corresponding to an integrated luminosity of $1.0\,{\rm fb}^{-1}$. Several angular observables are measured in bins of the dimuon invariant mass squared, $q^{2}$. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be $q_{0}^{2} = 4.9 \pm 0.9 \,{\rm GeV}^{2}/c^{4}$, where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions.
The production of J/ψ pairs in proton–proton collisions at a centre-of-mass energy of 7 TeV has been observed using an integrated luminosity of 37.5 pb−1 collected with the LHCb detector. The ...production cross-section for pairs with both J/ψ in the rapidity range 2<yJ/ψ<4.5 and transverse momentum pTJ/ψ<10 GeV/c isσJ/ψJ/ψ=5.1±1.0±1.1 nb, where the first uncertainty is statistical and the second systematic.
Decays of b hadrons into final states containing a D0 meson and a muon are used to measure the bb¯ production cross-section in proton–proton collisions at a centre-of-mass energy of 7 TeV at the LHC. ...In the pseudorapidity interval 2<η<6 and integrated over all transverse momenta we find that the average cross-section to produce b-flavoured or b¯-flavoured hadrons is (75.3±5.4±13.0) μb.
A search for the doubly charmed baryon Xi_cc^+ in the decay mode Xi_cc^+ -> Lambda_c^+ K^- pi^+ is performed with a data sample, corresponding to an integrated luminosity of 0.65/fb, of pp collisions ...recorded at a centre-of-mass energy of 7 TeV. No significant signal is found in the mass range 3300-3800 MeV/c^2. Upper limits at the 95% confidence level on the ratio of the Xi_cc^+ production cross-section times branching fraction to that of the Lambda_c^+, R, are given as a function of the Xi_cc^+ mass and lifetime. The largest upper limits range from R < 1.4 x 10^-2 for a lifetime of 100 fs to R < 3.4 x 10^-4 for a lifetime of 400 fs.
Apart from monitoring nuclear reactor parameters, the DANSS neutrino experiment is aimed at searching for sterile neutrinos through a detailed analysis of the ratio of reactor antineutrino spectra ...measured at different distances from the reactor core. The light collection system of the detector is dual, comprising both the vacuum photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs). In this paper, the techniques developed to calibrate the responses of these photodetectors are discussed in detail. The long-term stability of the key parameters of the detector and their dependences on the ambient temperature are investigated. The results of detector light yield measurements, performed independently with PMTs and SiPMs are reported.
An analysis of B±→DK± and B±→Dπ± decays is presented where the D meson is reconstructed in the two-body final states: K±π∓, K+K− and π+π−. Using 1.0 fb−1 of s=7TeVpp collisions, measurements of ...several observables are made including the first observation of the suppressed mode B±→π±K∓DK±. CP violation in B±→DK± decays is observed with 5.8σ significance.
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