V. A. Kuznetsov

TARGET DEPENDENCE OF RELATIVISTIC DEUTERON FRAGMENTATION INTO CUMULATIVE PIONS

The power value of the A-dependence of the cross-section for 4.5 GeV/nucleon deuteron fragmentation into cumulative pions has been measured on carbon, aluminium, copper and lead nuclei for cumulative numbers within 0.8-1.2. The mean value is equal to 0.27 ± 0.09 in this interval. The target atomic weight dependence significantly differs from the volume type dependence on the atomic weight of fragmenting nucleus.

Tensor Ayy and vector Ay analyzing powers in the 1H(d,d')X and 12C(d,d')x reactions at initial deuteron momenta of 9 GeV/c in the region of baryonic resonance excitation

The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon have been measured. The range of measurements corresponds to the baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being in good agreement with the previous results demonstrate an approximate

Measurement of the tensor analyzing power Ayy in the inelastic scattering of 4.5-GeV/c deuterons on beryllium at an angle of 80 mrad

t

Measurement of the differential cross section and of the tensor and vector analyzing powers for the fragmentation of 4.5-GeV/c deuterons on beryllium in the reaction involving proton emission at an angle of 80 mrad

scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role of the spin-dependent part of the elementary amplitude of the NN->NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon has been measured. The range of measurements corresponds to the baryonic resonance excitation with masses of ∼2.2–2.6 GeV/c2. The Ayy data, being in good agreement with the previous results, demonstrate an approximate t scaling up to −1.5 (GeV/c)2. The large values of Ay show a significant role of the spin-dependent part of the elementary amplitude of the NN → NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.

Measurements of the Vector and Tensor Analyzing Powers of the Inelastic Scattering of Deuterons on Nuclei in the Vicinity of Baryonic Resonances Excitation

The tensor analyzing power Ayy and the vector analyzing power Ay for the inelastic scattering of 4.5-GeV/c deuterons on beryllium nuclei at angle of about 80 mrad are measured in the vicinity of baryon-resonance excitation. These new data, presented as a function of t, comply well with the results of previous 4.5-, 5.5-, and 9-GeV/c measurements at zero angle in overlapping regions of t; all available data are described by a unified dependence on |t| upto about 0.9 (GeV/c)2. The experimental results are compared with the results of calculations performed within the multiple-scattering model and the model involving omega-meson exchange in the t channel.

Development of a data acquisition system for the SPHERE spectrometer

The invariant differential cross section, the tensor analyzing power Ayy, and the vector analyzing power Ay for the reaction 9Be(d, p)X are measured at an initial deuteron momentum of 4.5 GeV/c and a proton detection angle of about 80 mrad. The data obtained for the differential cross section are consistent with the results of measurements at 3.5 and 5.78 GeV/c and a proton emission angle of 2.5°. The values found for the tensor analyzing power Ayy are compared with similar data obtained previously for the deuteron-fragmentation process occurring on a carbon target at various values of the initial deuteron momentum and leading to proton emission at zero angle. The data on the differential cross section for the reaction 9Be(d, p)X can be satisfactorily described within the relativistic impulse approximation by using standard deuteron wave functions; however, the approach based on this conceptual framework proves to be inadequate in dealing with data on the tensor analyzing power. These results indicate that it is necessary either to change the method for describing the relativistic deuteron or to take into account additional mechanisms.

Measurement of the tensor analyzing power Ayy in the inelastic scattering of deuterons in the vicinity of excitation of baryonic resonances

Vector Ay and tensor Ayy analyzing powers of the inelastic scattering of deuterons with the momenta of 4.5 GeV/c on 9Be and 9 GeV/c on 1H and 12C at an angle of ∼80 mr in the vicinity of the excitation of baryonic resonances with masses between 1200 and 2200 MeV/c2 have been measured. The values of parameter Ay suggest that the role of the spin‐dependent part of the NN → NN* elementary processes is significant. The new Ayy data are in good agreement with the previous data at 4.5, 5.5 and 9 GeV/c, obtained at a zero angle, in an overlapping region of t. The results of the experiments are compared with the calculations within the PWIA and ω‐meson exchange model. The data obtained show that polarization observables of (d,d′) reaction in the vicinity of the excitation of baryonic resonances may be used to study their properties.

Measurement of the Tensor-Analyzing Power A yy in Deuteron Breakup at 4.5 GeV/c and 80 mr

Abstract The 4π-detector SPHERE for studying multiple particle cumulative production is currently under construction at the Laboratory of High Energies, JINR, Dubna. This paper briefly describes the present status and future developments of the data acquisition system for this setup. A multiprocessor system based on VMEbus will be implemented for parallel readout, event-building, and data preprocessing. A workstation will be used for data analysis and experimental control. The investigation has been performed at the Laboratory of High Energies, JINR.