P. Mazzanti

Study of D+ and D− Feynman's x distributions in π−-nucleus interactions at the SPS

Abstract Experiment WA82 studied charm production by a π− beam of 340 GeV/c at the CERN Ω′ spectrometer, using a silicon microstrip vertex detector and an impact parameter trigger. Results on the xF distributions of D+ and D− mesons are presented and discussed. A clear excess of D− over D+, increasing at high xF, is observed.

Measurements of charmed-meson production in interactions between 350 GeV/c π− particles and nuclei

Abstract Charmed-meson production by 350 GeV/c π − particles incident on copper and tungsten targets has been studied in the WA92 experiment, performed at the CERN Ω′ spectrometer. Results obtained are reported and discussed. Reconstruction of decays from the set D 0 → K − π + D 0 → K − π − π + π + , D s + → φπ + and charge conjugates has yielded a sample of 7280 ± 108 charmed mesons, produced with χ F > 0, ( χ F ) = 0.18 and〈 p T 2 〉 = 1.86 ( GeV / c ) 2 . Assuming a relationship σ = σ 0 A α between the cross section, σ, per nucleus of mass A and the nucleonic cross section, σ 0 the α value found for the detected charmed particles is 0.95 ± 0.06 ± 0.03. Taking α = 1, the measured cross sections per nucleon for χ F > 0 production are 7.78 ± 0.14 ± 0.52 μ b for D 0 / D 0 , 3.28 ± 0.08 ± 0.29 μ b for D + /D − and 1.29 ± 0.16 ± 0.33 μ b for D s + /D s − . Differential cross sections with respect to χ F and p T 2 have been determined for the various types of charmed meson, and particle-antiparticle asymmetries have been analysed.

Utilizing widely distributed computational resources efficiently with execution domains

Wide-area computational grids have the potential to provide large amounts of computing capacity to the scientific community. Realizing this potential requires intelligent data management, enabling applications to harness remote computing resources with minimal remote data access overhead. We define execution domains, a framework which defines an affinity between CPU and data resources in the grid, so applications are scheduled to run on CPUs which have the needed access to datasets and storage devices. The framework also includes domain managers, agents which dynamically adjust the execution domain configuration to support the efficient execution of grid applications. In this paper, we present the execution domain framework and show how we apply it in the Condor resource management system.

Measurement of the Ds→μνμ branching fraction and of the Ds decay constant

Abstract Using interactions of 350 GeV /c π − in copper and tungsten targets, the branching fraction for the leptonic decay B ( D s → μν μ ) is measured to be (0.83±0.23 stat. ±0.06 syst. ±0.18 B ( D s → ϕπ ) )%. The resulting value for the D s decay constant is f D s =323±44±12±34.

Production of neutral strange particles in νμd2 and νμd2 charged current interactions

The inclusive production of K0, Λ and Λ in charged-current (anti) nuetrino interaction in deuterium is studied, using the BEBC bubble chamber exposed to the CERN-SPS wide band (anti) neutrino beam. In a selected sample of 8600 charged current νμd2 and 6100νμd2 interactions, 700 K0, 448 Λ and 20 Λ particles were observed. The interactions have been separated in interactions on neutrons and on protons. The production properties are studied in terms of various kinematical variables. The associated production of strange particles, the production of K∗±(890) and of Σ±(1385) and the inclusive Λ polarization are discussed. The experimental results are compared with the predictions of the Field-Feynman and the Lund fragmentation models.

A QCD analysis of the 〈p2T〉 behaviour observed in recent semi-inclusive neutrino data

Abstract We present a comparison of QCD predictions with recent semi-inclusive data from the BEBC neutrino experiment on neon. We find, in particular, that the invariant hadronic mass, W , is a much more convenient variable than Q 2 to put in evidence the variations of the hadron 〈 p 2 T 〉 predicted by QCD. The results of the analysis are midly encouraging for QCD. There are points, though, which need further clarification from experiments.

Production of neutral strange particles in and νμd2 charged current interactions

The inclusive production of K0, Λ and Λ in charged-current (anti) nuetrino interaction in deuterium is studied, using the BEBC bubble chamber exposed to the CERN-SPS wide band (anti) neutrino beam. In a selected sample of 8600 charged current νμd2 and 6100νμd2 interactions, 700 K0, 448 Λ and 20 Λ particles were observed. The interactions have been separated in interactions on neutrons and on protons. The production properties are studied in terms of various kinematical variables. The associated production of strange particles, the production of K∗±(890) and of Σ±(1385) and the inclusive Λ polarization are discussed. The experimental results are compared with the predictions of the Field-Feynman and the Lund fragmentation models.

A study of kinematical correlations between charmed particles produced in π-Cu interactions at s=26 GeV

Abstract A sample of 475 events, in which two charmed-particle decays are observed, is analyzed to determine distributions of two-particle kinematic variables. One charmed particle with x F > 0 is fully reconstructed and the other is at least partially recontructed. The distributions of Δo and p T 2 are compared with a next-to-leading order QCD calculation.

STUDY OF CHARM CORRELATIONS IN PI(-)-N INTERACTIONS AT ROOT-S-APPROXIMATE-TO-26 GEV

Abstract We report on the associated production of charmed hadrons in π−-nucleon interactions at s ≃26 GeV at the CERN Ω′ spectrometer. Results on the azimuthal correlation of charmed particle pairs are presented and compared to the predictions of Next-to-Leading-Order QCD calculations.

Measurement of relative branching fractions for D+→K−K+K+ and Ds+→π−π+π+ decays

Abstract The decay modes D s + → π − π + π + and D + → K − K + K + have been studied in the hadroproduction experiment WA82. The following ratios of branching fractions have been measured: , , .