Experimental estimation of the charm-production cross section in pp interactions at 70 GeV/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 Mice IHEP accelerator (Protvino). The experimental proced ure used and the data-selection methods are described. Data obtained by usi ng a quickly cycling bubble chamber and a magnetic spectrometer are analyze d. The number of inelastic-interaction clients recorded in the chamber is 1 09 000, with the charge multiplicity being n(ch) greater than or equal to 4 . The corresponding statistics are 4.96 event/mub. Part of the events were recorded in the magnetic spectrometer. Three three-prong decays of charged particles near the primary vertex are round on the films, two of these bein g recorded with the spectrometer. All three are interpreted as D- decays. T wo neutral decays observed simultaneously in the chamber and in the spectro meter are interpreted as (D) over bar (0) decays. The total cross section f or c (c) over bar production in the Feynman variable region -1 < x(F) < + 1 is estimated at sigma (c (c) over bar) = 1.6(-0.7)(+1.1) (stat.) +/- 0.3 ( syst.) mub. The cross-section values and the mean values < \x(F)\> and <p(p erpendicular to)> 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 7 0 GeV and with those predicted by perturbative QCD. (C) 2001 MAIK "Nauka/In terperiodica".