F. Meijers

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

Abstract Intermittent behaviour is observed in π + p and K + p collisions at 250 GeV/ c . It is stronger there than in O 16 emulsion, but weaker than in e + e − collisions. A jet cascading mechanism is, therefore, the most likely interpretation. Presently used fragmentation models do not (fully) reproduce the effect, suggesting that an improvement of the hadronization picture is needed.

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.

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.

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

Inclusive production of vector mesons in π+p interactions at 250 GeV/c

\sqrt s = 22

Inclusive meson resonance production inK+p interactions at 250 GeV/c

GeV, for full phase space as well as for intervals in rapidity, azimuthal angle and transverse momentum. In general, the multiplicity distribution is well described by a negative binomial. From comparison of the distribution for negative or positive particles to that of all charged particles, cascading is favoured as an interpretation over stimulated emission. Interesting consequences follow from a comparison of our results to those at collider energies and toe+e− data at comparable energy. Furthermore, evidence is given that the multiplicity distribution is not exactly of negative binomial type in every (connected or disconnected) phase space region.