Experimental Estimation of the Charm-Production Cross Section in pp Interactions at 70GeV/c with the Aid of the SVD Setup.

Charmed-particle production in pp interactions at 70 GeV/c was studied with the SVD setup at the IHEP accelerator (Protvino). The experimental procedure used and the data-selection methods are described. Data obtained by using a quickly cycling bubble chamber and a magnetic spectrometer are analyzed. The number of inelastic-interaction events recorded in the chamber is 109000, with the charge multiplicity being n[sub ch] ≥ 4. The corresponding statistics are 4.96 event/µb. Part of the events were recorded in the magnetic spectrometer. Three three-prong decays of charged particles near the primary vertex are found on the films, two of these being recorded with the spectrometer. All three are interpreted as D[sup -] decays. Two neutral decays observed simultaneously in the chamber and in the spectrometer are interpreted as &Dmacr;[sup 0] decays. The total cross section for c&cmacr; production in the Feynman variable region -1 < x [sub F] < +1 is estimated at σ (c&cmacr;) = 1.6[sup +1.1][sub -0.7](stat.) ± 0.3 (syst.) µb. The cross-section values and the mean values 〈x[sub F]〉 and 〈p&perp〉 for D mesons are compared with other experimental results in the energy range 58-800 GeV. The data of this experiment are compatible with the cross-section estimates obtained in the beam-dump experiment at 70 GeV and with those predicted by perturbative QCD. [ABSTRACT FROM AUTHOR]