[en] A selection of the Photon Gluon Fusion (PGF) process with light quarks for deep inelastic scattering events is presented. This process is directly sensitive to gluon polarization and our goal is to find out the most effective selection on a sample of events simulated for the SMC experiment. We compare two general multi-class classification methods - Bayes method and neural network with a conventional selection procedure. The neural network algorithm presented here is a modification of method belonging to the family of directional minimization algorithms. This method is convenient and effective for photon gluon fusion selection and determination of gluon polarization. Finally we present the estimation for precision of gluon polarization for neural network method. (author)

[en] The T2K long-baseline neutrino oscillation experiment is running in Japan. The primary goals of the T2K are measurement of the mixing angle θ₁₃, and precise measurements of the mixing angle θ₂₃ and of the mass difference Δm²₂₃. The installation of the near detector complex was completed and first data were already registered. This article presents operation of the Side Muon Range Detector, a component of the Off-Axis near detector. Detector concept and implementation are presented, followed by a description of cosmic muon track reconstruction algorithm and finally current status. (author)

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No abstract available

[en] A direct proof of the existence of ν_μ→ν_τ oscillations is important. This proof can be obtained by an observation of the production of taons in charge current reactions ν_τ + N → τ + X. The influence of polarization on the characteristics of the CC events and on the efficiency of their selection is discussed. The neural network method is used to select τ leptons produced in ν_τ interactions. (author)

[en] We report an early result from the ICARUS experiment on the search for a ν_μ → ν_e signal due to the LSND anomaly. The search was performed with the ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS neutrinos from CERN at an average energy of about 20 GeV, after a flight path of ∝730 km. The LSND anomaly would manifest as an excess of ν_e events, characterized by a fast energy oscillation averaging approximately to sin ²(1.27Δ m²_newL/E_ν)∼ 1/2 with probability P_νμ→νe = 1/2 sin²(2θ_new). The present analysis is based on 1091 neutrino events, which are about 50 % of the ICARUS data collected in 2010-2011. Two clear ν_e events have been found, compared with the expectation of 3.7 ± 0.6 events from conventional sources. Within the range of our observations, this result is compatible with the absence of a LSND anomaly. At 90 % and 99 % confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation probabilities left angle P_νμ→νe right angle ≤ 5.4 x 10^-3 and left angle P_νμ→νe right angle ≤ 1.1 x 10^-2 are set respectively. The result strongly limits the window of open options for the LSND anomaly to a narrow region around (Δm², sin²(2θ))_new = (0.5 eV², 0.005), where there is an overall agreement (90 % CL) between the present ICARUS limit, the published limits of KARMEN and the published positive signals of LSND and MiniBooNE Collaborations. (orig.)

[en] We report an updated result from the ICARUS experiment on the search for ν_μ →ν _e anomalies with the CNGS beam, produced at CERN with an average energy of 20 GeV and traveling 730 km to the Gran Sasso Laboratory. The present analysis is based on a total sample of 1995 events of CNGS neutrino interactions, which corresponds to an almost doubled sample with respect to the previously published result. Four clear ν_e events have been visually identified over the full sample, compared with an expectation of 6.4 ±0.9 events from conventional sources. The result is compatible with the absence of additional anomalous contributions. At 90 % and 99 % confidence levels, the limits to possible oscillated events are 3.7 and 8.3 respectively. The corresponding limit to oscillation probability becomes consequently 3.4 x 10^-3 and 7.6 x 10^-3, respectively. The present result confirms, with an improved sensitivity, the early result already published by the ICARUS Collaboration. (orig.)

[en] Electron recombination in liquid argon (LAr) is studied by means of charged particle tracks collected in various ICARUS liquid argon TPC prototypes. The dependence of the recombination on the particle stopping power has been fitted with a Birks functional dependence. The simulation of the process of electron recombination in Monte Carlo calculations is discussed. A quantitative comparison with previously published data is carried out

[en] The ICARUS collaboration has demonstrated, following the operation of a 600 ton (T600) detector at shallow depth, that the technique based on liquid argon time projection chambers is now mature. The study of rare events, not contemplated in the standard model, can greatly benefit from the use of this kind of detectors. In particular, a deeper understanding of atmospheric neutrino properties will be obtained thanks to the unprecedented quality of the data ICARUS provides. However if we concentrate on the T600 performance, most of the ν_μ charged current sample will be partially contained, due to the reduced dimensions of the detector. In this article, we address the problem of how well we can determine the kinematics of events having partially contained tracks. The analysis of a large sample of atmospheric muons collected during the T600 test run demonstrates that, in case the recorded track is at least one meter long, the muon momentum can be reconstructed by an algorithm that measures the multiple Coulomb scattering along the particle's path. Moreover, we show that momentum resolution can be improved by almost a factor two using an algorithm based on the Kalman filtering technique. (orig.)

[en] The COMPASS Collaboration at CERN has investigated the reaction π^-γ → π^-π^-π⁺ embedded in the Primakoff reaction of 190 GeV pions scattering in the Coulomb field of a lead target, π^-Pb → π^-π^-π⁺ Pb. Exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at momentum transfer below 0.001 (GeV/c)². Using a partial-wave analysis the amplitudes and relative phases of the a₂(1320) and π₂(1670) mesons have been extracted, and the Coulomb and the diffractive contributions have been disentangled. Measuring absolute production cross sections we have determined the radiative width of the a₂(1320) to be Γ₀(a₂(1320) → πγ) = (358 ± 6_stat ± 42_syst) keV. As the first measurement, Γ₀(π₂(1670) → πγ) = (181 ± 11_stat ± 27_syst) keV . (BR^PDG_f2π/BR_f2π) is obtained for the radiative width of the π₂(1670), where in this analysis the branching ratio BR^PDG_f2π = 0.56 has been used. We compare these values to previous measurements and theoretical predictions. (orig.)