R. Lednický

Single-particle inclusive spectra of charged particles in pp interactions at 22.4 GeV/c

The inclusive spectra for pp collisions at 22.4 GeV/c are investigated. We show that the transverse momentum distributions resemble those in high-energy pp interactions and discuss the influence of annihilation processes on the pT2 distributions. The invariant inclusive cross section for pions in the central region is found to be 28 ± 1 mb. A charge asymmetry is indicated by the y∗ spectrum in the central region, the asymmetry parameter having the value 0.15 ± 0.01. Finally, we estimate the upper limit of the diffraction dissociation of the beam particle to be 3.68−0.15+0.45 mb.

Inclusive ϱ0 production in pp interactions at 22.4 GeV/c

Abstract Inclusive ϱ 0 production has been investigated in p p reactions at 22.4 GeV/ c . The total cross section for ϱ 0 production is 8.1 ± 2.0 mb. The average ϱ 0 s per event is 0.17 ± 0.03. The average transverse momentum, as obtained by extrapolation of a fitted simple exponential to the p T 2 distribution, is 0.52 ± 0.12 GeV/ c . The Feynman x and c.m. rapidity distributions show ϱ 0 to be “centrally” produced.

MULTIPARTICLE PRODUCTION IN ANTIPROTON COLLISIONS

The special interest in antinucleon-nucleon interactions is in particular connected with the unique possibility of studying annihilation reactions in which the initial baryons and antibaryons turn into mesons. A characteristic feature of these processes is the large multiplicity of produced particles (as compared with other reactions where about half the c.m. energy is carried off by leading particles) which allows one to study multiparticle production even at relatively low energy. This interest is reflected by the fact that a whole series of Conferences has been devoted to IVNinteractions: Chexbres (1972), Liblice-Prague (1974), Stockholm (1976), BarrStrasbourg (1978), Bressanone (1980) and Santiago de Compostela (1982). Similar symposia have also been organized in Argonne (1958), Syracuse (1975) and LomaKoli (1975). These conferences embraced also other interesting topics of antiproton physics, such as ~-atoms, baryonium spectroscopy etc., which will certainly achieve a: new qualitative level in near future with the help of antiproton cooling devices (e.g., LEAR project [1]) due to the enormous increase in beam intensity by a factor of 103 and the amazing mass resolutions of a few keV. The new exciting data at very high energies are expected to appear from the pp-collider, ingeniously exploiting equal proton and antiproton masses and opposite charges to accelerate and collide them simultaneously in the same accelerator. In fact, interesting results on multiparticle production at 540 GeV in c.m.s, have recently been obtained [2, 3], e.g. clear hard parton jets have been observed allowing a check of quantum chromodynamics (QCD) predictions. I will concern myself mainly with the questions of multiparticle production in pp,interactions and also in other processes and will discuss the experimental data in terms of Regge phenomenology and quark-patton models (QM). It should be noted that the simplest QM based on SU(6) spin statistics [4, 5] predicted abundant resonance production in agreement with experiment. Since resonances yield more direct and richer information on the production mechanism, as compared with pions, kaons or nucleons, the study of resonance production is of great interest. *) Lecture given at the Arctic School of Physics 1982, Ak/islompo, Finland, August 1-- 13, 1982.

On the Sensitivity of Nucleon-nucleon Correlations to the Form of Short Range Potential

Nucleon-nucleon correlation characteristics are calculated for several phenomenological and realistic strong potentials. The results show that a square-well potential reasonably well approximates the nucleon-nucleon interaction if one calculates the correlations between nudeons generated in a region with an r.m.s. radius larger than 1·5–2 fm. And vice versa, the correlations of nucleons emitted from a smaller generation region are sensitive to the form of assumed nucleon-nucleon potential.

Observation of the dependence of the interference effect of identical pions on pion pair velocity in inclusive ¯pp-interactions at 22·4 GeV/c

The Bose-Einstein interference effect is studied using 7333 events of ¯pp-interactions withnch≧6 at 22·4 GeV/c. An essential dependence of the strength of this effect on the pion pair velocity is observed. An indication is obtained that processes with essentially different time characteristics (τ<1 fm and τ>2 fm) contribute to ¯pp-interactions at 22·4 GeV/c. The interpretation based on abundant resonance production in high energy collisions is discussed.

Inclusive production of Δ++ (1236) in pp interactions at 22.4 GeV/c

Abstract The inclusive and semi-inclusive production of Δ ++ (1236) is investigated in p p interactions at 22.4 GeV/ c . The Δ ++ cross section is 1.78 ± 0.18 mb in the region of | t p Δ | ⩽ 0.74 (GeV/ c ) 2 . The differential cross section has been studied as a function of transverse and longitudinal variables. Evidence for the one-pion exchange contribution to the Δ ++ inclusive process has been obtained from the decay angular distributions of the Δ ++ .

Inelastic\(\bar p\)p interactions at 22.4 GeV/c compared withe+e− annihilation into hadrons

AbstractThe 22.4 GeV/c

Femtoscopic correlations in multiparticle production and Beta-Decay

\bar p