I. V. Ajinenko

Maximum particle densities in rapidity space of π+ p, K+ p and pp collisions at 250 GeV/c

Abstract In a study of π + p, K + p and pp collisions at √ s =22GeV in the european hybrid spectrometer (EHS), the maximum charged particle density per given rapidity interval is found to rise linearly with charged particle multiplicity, independent of beam particle type and practically independent of energy between 22 and 900 GeV. An anomalous π + p event is found with ten particles within the very narrow rapidity interval Δy =0.098.

Charged particle production inK + p, π p andpp interactions at 250 GeV/c

New results are reported on inclusive charged particle production inK+p,π+p andpp collisions at 250 GeV/c. Inclusive longitudinal and transverse momentum spectra of positively and negatively charged particles are presented. Scaling in the fragmentation regions and scaling violation in the central c.m. region is investigated in detail. The topological pseudo-rapidity densities are shown to scale in the c.m. energy range from 22 to 900 GeV.

Inclusive Production Cross-Sections of Resonances in 32-GeV/c K+ p Interactions

Abstract The inclusive production of resonances is systematically studied in K + p interactions at 32 GeV/ c . Total production cross sections are given for three baryon resonances, five vector and three 2 + tensor mesons. We also compare the central and fragmentation components of the total production cross sections with quark model predictions.

Rapidity dependence of negative and all-charged multiplicities in non-diffractive π+p and pp collisions at 250 GeV/c

Multiplicity distributions of all charged and of negative particles for non (single)-diffractive events in π+p and pp collisions at 250 GeV/c (s=22 GeV) are presented for various rapidity intervals. The data are well described by the negative binomial distribution. The π+p and pp data are different for full phase space, but similar for the central region. In the central region, the relation kch≈12 k− holds for all charged and negative multiplicities. This favours the interpretation in terms of cascade models above (partial) stimulated emission models.

Intermittency effects in π+p and K+p collisions at 250 GeV/c

Abstract Density fluctuations are studied in rapidity, pseudo-rapidity and azimuthal angle, as well as in two-dimensional distributions in rapidity and azimuthal angle. Evidence for intermittency, i.e. rise of factorial moments with increasing resolution, is found in all four distributions. Intermittency is stronger in two dimensions than in one, but the difference is smaller than would be expected from the production of “pencil jets”. Contrary to what would be expected from Bose-Einstein interference, no increase by a factor 2 is found in slope when the analysis is restricted to particles of identical charge.

Charged pion production in 32GeV/c K+p interactions

Final data on topological cross sections are presented. Inclusive single particle distributions for the reactionsK+p→ π±X at 32 GeV/c are discussed and compared with data at lower energies. Early scaling in the fragmentation regions is confirmed, while cross sections in th central region continue to rise with energy even faster than inpp interactions. Thex-andpT-dependence of the π+/π− ratio inK+p interactions is discussed and a comparison of reactionsK+p→ π±X andK−p→ π±X at 32 GeV/c is made in the context of constituent models. We also present transverse momentum distributions, show prominent seagull effects and study how they are influenced by resonance production.

InclusiveK*+(892) andK*0(892) production inK+p interactions at 32 GeV/c

Total and semi-inclusive cross sections, longitudinal and transverse momentum distributions and spin density matrix elements of theK*+(892) andK*0(892) produced in the inclusive reactionsK+p→K*+(892)+X andK+p→K*0(892)+X at 32 GeV/c are studied in detail. The inclusive spectra of theK*(892) and their decay products are compared with pion and neutral kaon production. TheK*+(892) andK*+(892) are dominantly produced by kaon fragmentation processes. The dependence of average transverse momentum vs.x for resonances has been investigated for the first time.

Phase space dependence of the multiplicity distribution in π+ andpp collisions at 250 GeV/c

AbstractThe charged particle multiplicity distribution has been studied for non-single-diffractive π+p andpp collisions at

Genuine higher-order correlations in π+p and K+p collisions at 250 GeV/c

\sqrt s = 22