Transverse momenta of secondaries from 200 GeV/c proton-nucleus interactions

A study of 100 interactions, produced by secondary particles from 200 GeV/c proton interactions in nuclear emulsions, has been made to estimate the transverse momenta of the secondary particles. The data have been analysed by different methods of energy estimation and the weighted average values ofp _t have been compared as estimated from various methods. An average value ofp _t equal to 0.38 ± 0.03 GeV/c, in proton-nucleus interactions at 200 GeV/c, has been obtained from the production mechanism method.     

Multiparticle rapidity clustering in 200 GeV/cπ−p interactions

A study of multiparticle rapidity clustering is made using a generalized rapidity-gap method. The data for events with ?6 charged particles are compared to what would be expected from uncorrelated particle production. We find clear evidence for cluster production. The data are consistent with ～ 20% of all charged particles being produced in clusters of two charged particles; clusters of higher multiplicity are not required.     

Leading particle distributions in 200 GeV/c p+A interactions

Distributions of the leading positive particle have been measured in collisions of a 200 GeV/c proton beam with hydrogen, Mg, Ag and Au targets using the FNAL Hybrid Spectrometer. Estimates of the rapidity loss of the projectile have been obtained as a function of the target mass, the multiplicity of negative particles and the number of recoil protons. We obtained a lower limit of the rapidity loss of 2.0±0.2 for central p+Au collisions. The impact parameter dependence of the momenta of the first few leading particles has also been investigated with important implications to estimates of energy densities obtained in central collisions.     

K1±(892) Production in π−N interactions at 200 GeV/c

K^1±(892) production is studied in the reaction π^?N → K_S⁰K_S⁰ + X where X includes up to five observed charged particles. An excess of K^1? over K¹⁺ is observed for Feynman-x > 0.1. The ratio of K¹⁺ to K^1? decreases with x as predicted by QCD counting rules. K_S⁰ and K¹ production are compared to recent D and D¹ data from other experiments.     

Production cross sections of multiply charged fragments in heavy ion interactions at 150–200 MeV/nucleon

A total of 1720 ¹⁶O-emulsion nucleus interactions at 150–200 MeV/nucleon have been investigated. Production cross sections of multiply charged projectile fragments are given. It is found that the cross section for the production of N, C, B and Be projectile fragments in ¹⁶O-nucleus interactions is similar at 0.2 and 2 GeV/nucleon. The fragmentation cross sections for Li and He are larger at 0.2 than at 2 GeV/nucleon.     

Production of charged kaons in proton-nucleus and nucleus-nucleus collisions at 200 GeV/nucleon

Production of charged kaons in proton-sulphur, proton-gold, sulphur-sulphur and oxygen-gold collisions at 200 GeV/nucleon has been studied in the NA35 Streamer Chamber experiment. Rapidity and transverse mass distributions as well as mean multiplicities were obtained. The results are compared with nucleon-nucleon data and with model predictions.Deceased     

Shape distortions of meson resonances produced in hadron interactions atP T≧2 GeV/c

Using the ARGUS detector at thee ⁺ e ^– storage ring DORIS II, flavour-dependent kaon production inB meson decays has been studied. Using the leptons as flavour tags, it has been possible to separately measure the multiplicities ofK ⁺,K ^– andK _s ⁰ in inclusiveB decays and in semileptonicB decays. The kaon production in semileptonicB decays was further used to estimate the ratio of charmed decays over all decays, and thus also the fraction of charmlessB decays.DESY, IfH Zeuthen     

Production of helium projectile fragments in {16O－emulsion interactions at 4.5 A GeV/c

The measurements of partial production cross sections of the multiple helium projectile fragments emitted at 4.5 A GeV/c {}^{16}O－Em interactions are reported. We have studied the production rate of helium projectile fragments due to fragmentation of {}^{16}O ions and compared it with that obtained from different projectiles at various energies. The dependence of on the mass number of the incident beams is formulated. The multiplicity distributions of the helium fragments produced in {}^{16}O－Em interactions at different energies exhibit Koba－Nielson－Olesen (KNO) scaling. The correlation of helium projectile fragments and target fragments is also investigated and it is found that the average of target fragments is increased with the decrease of the number of helium fragments in peripheral interactions.     

Topological cross sections and charged particle multiplicities inpp interactions at 360 GeV/c

Using data obtained with EHS equipped with the Rapid Cycling Bubble Chamber (RCBC) exposed to a proton beam of 360 GeV/c, we calculate topological cross sections. We present in great detail the procedure and the techniques used to correct raw data. Finally, we give multiplicity moments and multiplicity correlations and we compare the values obtained in our experiment, together with data at other energies, with different models.     

Structures and angular distributions of slow and relativistic charged particles produced in 7Li-emulsion interactions at 3 GeV/c per projectile nucleon

Experimental results on the multiplicity distributions of various particles produced in the interactions of ⁷Li with emulsion nuclei at a momentum of 3 GeV/c per projectile nucleon are reported. A comparison with data on collisions induced by other nuclei at a nearly identical momentum per nucleon is presented in order to reveal the dependence on the projectile mass. The internal structure of ⁷Li is explored by studying the projectile fragment. The mean multiplicity of shower particles, 〈n _s〉, induced by ⁷Li is found to be less than that in the case of ⁶Li projectiles. The angular distributions of target fragments and relativistic charged secondaries are investigated. No shock-wave phenomena are observed. Forward-to-backward ratios are calculated for each case. The probability distributions for relativistic secondaries produced per unit rapidity are studied in detail, along with the rapidity densities and their dependence on the projectile and the target mass. A comparison of the angular spectra of shower particles produced in central and peripheral collisions supports the limiting-fragmentation hypothesis. The collisions in question seem to become more central with increasing shower-particle multiplicity.     

Pion-proton elastic scattering at 200 GeV/c

Recent measurements of differential and elastic cross-sections, slope parameters and ratios of the real and imaginary parts of the forward scattering amplitudes for pion-proton elastic scattering at 200 GeV/c have been fitted by using a simple Regge pole model with phenomenological residue functions. The computed results for total cross-sections have also been compared with the experimental data.     

Single particle inclusive spectra of charged particles from antiproton-proton interactions at 5.7 GeV/c

A systematic study of single particle inclusive spectra of charged particles from ¯pp interactions at 5.7 GeV/c is presented and discussed in the framework of the Mueller-Regge approach to inclusive reactions. A comparison of our results with data at other energies points to specific properties of antiproton-proton interactions.I have greatly benefited from discussions with Dr. J. Cvach and Dr. V. imák. To Dr. V. imák I am also indebted for the encouragement during the preparation of this paper.     

Antiproton-neutron interactions at 100 GeV/c

From an exposure of the 30-inch deuterium filled bubble chamber to a 100 GeV/c antiproton-enriched beam at FNAL, we have calculated the topological cross sections for antiproton-neutron interactions with three or more charged particles in the final state. A comparison of our data with pn data at the same momentum allows us to estimate the annihilation contribution to each multiplicity, and hence calculate the average value, and width, of the annihilation multiplicity distribution. Our results are consistent with those from $\text{p}\text{p}$ data at 100 GeV/c, but depart from the trend of lower-energy $\text{p}\text{p}$ data.     

Λp interactions below 24 GeV/c

Λp interactions have been studied at momenta up to 24 GeV/c using a new bubble chamber technique. We find that the Λp elastic cross section has fallen to approximately 6 mb at the highest momentum. Results are presented on Λp→Λpπ⁺π^? for the first time above 5 $\text{GeV}\text{c}$.     

The production ofJ/ψ in 200 GeV/A oxygen-uranium interactions

The dimuon production in 200 GeV/nucleon oxygen-uranium interactions is studied by the NA 38 Collaboration. The production ofJ/ψ, correlated with the transverse energyET, is investigated and compared to the continuum, as a function of the dimuon massM and transverse momentumPT. A value of 0.64±0.06 is found for the ratio (ψ/Continuum at highET)/(ψ/Continuum at lowET), from which theJ/ψ relative suppression can be extracted. This suppression is enhanced at lowPT.