The results of analysis SERP-E-184 experiment data, obtained with 70 GeV proton beam irradiation of active target with carbon, silicon and lead plates are presented. For 3-prongs charged charmed mesons decays, event selection criteria were developed
and detection efficiency was calculated with detailed simulation using FRITIOF7.02 and GEANT3.21 programs. Signals of decays were found and charm production inclusive cross sections estimated at near threshold energy. The lifetimes and A-dependence of cross section were measured. Yields of D mesons and their ratios in comparison with data of other experiments and theoretical predictions are presented.
The results of treatment of data obtained in the SERP-E-184experiment Investigation of mechanisms of the production of charmed particles in proton-nucleus interactions at 70 GeV and their decays by irradiating the active target of the SVD-2 facility
consisting of carbon, silicon, and lead plates, are presented. After separating a signal from the two-particle decay of neutral charmed mesons and estimating the cross section for charm production at a threshold energy {sigma}(cv{c})=7.1 pm 2.4(stat.) pm 1.4(syst.) mub/nucleon, some properties of D mesons are investigated. These include the dependence of the cross section on the target mass number (its A dependence); the behavior of the differential cross sections d{sigma}/dpt2 and d{sigma}/dxF; and the dependence of the parameter {alpha} on the kinematical variables xF, pt2, and plab. The experimental results in question are compared with predictions obtained on the basis of the FRITIOF7.02 code.
Neutral pion number N0 distributions for each total number of particles in event Ntot=Nch+N0 are obtained. The scaled variance of neutral pion fluctuations, omega=D/<N0>, is measured. The fluctuations increase at Ntot >22. According to quantum statis
tics models it may indicate for the approaching to pion condensate conditions for high pion multiplicity in the system.
The results of data handling for E-184 experiment obtained with 70 GeV proton beam irradiation of active target with carbon, silicon and lead plates are presented. Two-prongs neutral charmed D0 and v{D}0 -mesons decays were selected. Signal / backgro
und ratio was (51+/-17) / (38+/-13). Registration efficiency for mesons was defined and evaluation for charm production cross section at threshold energy is presented: sigma(c^c) = 7.1 +/- 2.4(stat.) +/- 1.4(syst.) (mu/nucleon).
