Antiproton production cross-sections have been measured for p+C, C+C, C+Cu and C+Pb collisions at 3.65 GeV/nucleon.\(\bar p\) laboratory momentum and angle are 0.8 GeV/c and 24°. The target mass dependence parameter is found to be 0.43±0.1. A strong increase in antiproton yield is observed from p+C, d+C to C+C collisions. Projectile mass parameter is 1.2±0.2 for d+C to C+C. The construction and calibration of APAKI, an annihilation detector for\(\bar p\) identification, are also described.
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The multiplicity distributions and the correlations of different types of slow particles produced in 200A GeV oxygen-induced interactions with emulsion nuclei are presented. The experimental distributions are studied within the framework of the generalized Andersson-Otterlund-Stenlund (AOS) model for nucleus-nucleus interactions. The generalized (AOS) model fails to describe the present experimental data. Also a systematic comparison using the calculations of VENUS model is made. The grey-particles multiplicity is successfully reproduced by the theoretical multistring model VENUS, while the model is inadequate for explaining the distribution of black particles.
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Data were obtained using the streamer chamber spectrometer SKM-200 at a momentum of 4.5 GeV/c per incident nucleon. From the analysis of angular distributions of pi - mesons the anisotropy coefficient a for He-Li, He-C, C-Ne, C-Cu, C-Pb, O-Pb and Mg-Mg collisions was obtained. It has been shown that a is similar for symmetric systems of nuclei (He-Li and Mg-Mg) and increases slowly with mass numbers of projectile (Ap) and target (AT) for other pairs of nuclei. The anisotropy coefficient a increases linearly with the kinetic energy E*kin (in the CMS) for all pairs of nuclei. The qualitative agreement of our results with the predictions of the intranuclear cascade models has been observed.
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The focus of this experiment is on dimuons at low M T but the mass range up to the J ψ is also covered. Dimuons are measured over a wide rapidity interval, ranging from nearly central to very forward rapidities. Experimental results concerning the vector meson production in p-W and S-W interactions at 200 GeV/c/A as a function of the charged multiplicity are presented together with a comparison of the observed invariant mass spectra with the dimuon conventional sources in the mass region between the φ and J ψ mesons. The observed large difference in the shape and absolute value of p-W and S-W dimuon spectra cannot be explained in terms of a direct extrapolation of the p-p results.
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CENTRAL EVENTS: 10% OF SIG(GEOM).
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PRELIMINARY DATA FOR CENTRAL EVENTS.
Single particle distributions of π ± , K ± , p , p and d near mid-rapidity from 450 GeV/c p A and 200 GeV/c per nucleon SA collisions are presented. Inverse slope parameters are extracted from the transverse mass spectra, and examined for indications of collective phenomena. Proton and antiproton yields are determined for different projectile-target combinations. First results from 160 GeV/c per nucleon PbPb collisions are presented.
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PRELIMINARY DATA FOR CENTRAL EVENTS.
Experimental data on multiplicities and correlations of charged particles of different types produced in collisions of 4.5 A GeV/c carbon-12 with emulsion are reported and discussed. The data are compared with the results of other experiments on nucleus–nucleus and hadron–nucleus collisions. It is found that the particle production mechanism in nucleus–nucleus collisions is almost the same as in hadron–nucleus collisions. It is also observed that the shower particles' multiplicity distributions obey a KNO type scaling law, which supports the aforementioned result.
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Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 to 2.8 GeV and center-of-mass angles from 37° to 90°. The measured energy dependence of the cross section at θc.m.=90° is in agreement with the constituent counting rules.
Statistical and systematic errors have been added in quadrature. Photon energy and angle (in deg) are in center-of-mass system.
We detected 1–10 MeV neutrons at laboratory angles from 80° to 140° in coincidence with 470 GeV muons deep inelastically scattered from H, D, C, Ca, and Pb targets. The neutron energy spectrum for Pb can be fitted with two components with temperature parameters of 0.7 and 5.0 MeV. The average neutron multiplicity for 40<ν<400 GeV is about 5 for Pb, and less than 2 for Ca and C. These data are consistent with a process in which the emitted hadrons do not interact with the rest of the nucleus within distances smaller than the radius of Ca, but do interact within distances on the order of the radius of Pb in the measured kinematic range. For all targets the lack of high nuclear excitation is surprising.
The energy spectrum for neutrons emitted from a thermalized nucleus may be expressed as a multiplicity per unit energy d(M)/d(E)=(M/T**2)*E*exp(-E/T) in which E is the neutron energy, M is the total multiplicity (isotropic in the nuclear frame), and T is the nuclear temperature. A fit by the sum of two exponentials.
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