Charmonium production by 350 GeV/c negative pions incident on tungsten, copper and silicon has been studied in the WA92 experiment. J/psi and psi' mesons are identified through their decays into muon pairs and are selected in the Feynman-x range x(F) > 0. Inclusive J/psi and psi' cross-sections and J/psi differential cross-sections as functions of x(F) and p(T)(2) are measured. Assuming the relation sigma = sigma(0) A(a) between the nuclear cross-section, sigma, and the atomic mass, A, of a target nucleus, a fit to J/psi data for different targets yields alpha = 0.87 +/- 0.05 +/- 0.04. Taking alpha = 0.87, the cross-sections per nucleon for J/psi and psi' are sigma(0)(J/psi) = 216 +/- 5 +/- 13 nb and sigma(0)(psi') = 28 +/- 8 +/- 11 nb, and their ratio is sigma(0)(psi') / sigma(0)(J/psi) = 0.13 +/- 0.05 +/- 0.01. The measurements of charmonium production are compared with results on open-charm production previously obtained in the same experiment. The ratio between the J/psi cross-section and the charmed-meson cross-section, relating to the same experimental conditions, is found to be sigma(0)(J/psi) /sigma(0)(D (D) over bar) = (1.75 +/- 0.05 +/- 0.15) x 10(-2). (C) 1999 Published by Elsevier Science B.V. All rights reserved.
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|Titolo:||Inclusive J/psi and psi ' production in pi(-) -nucleus interactions at root s similar or equal to 26 GeV|
|Data di pubblicazione:||1999|
|Appartiene alla tipologia:||01a Articolo in rivista|