High Energy Multiparticle Production Research Articles

The multiple scattering model analysis of high energy multiparticle production on emulsion nuclei

Data on multiparticle production on emulsion nuclei in the range 50–400 GeV/c have been analyzed in the framework of multiple scattering model developed by Capella and Krzywicki. It is shown that under some reasonable assumptions multiple scattering type models qualitatively reproduce multiplicity distributions of relativistic charged particles, one-particle spectra and two-particle inclusive correlations.

Pi-ball configurations in high-energy multiparticle production

The authors investigate high-energy multiparticle production models in which Bose-Einstein symmetry leads to production of multi-pion final states with very high rapidity density in a limited rapidity region. They outline the possible experimental consequences and indicate where direct evidence of this phenomenon may be sought.

An extension of the generator functional technique; the general method of the correction of detection losses in high energy measurements

This paper deals with the correction of the cross sections of the high energy multiparticle production in the case when the detection of the secondary particles has a probability less than unity. Generalizing the usual generator functional technique we get a universal method. The possibility of getting the true distributions is proved under some conditions we have considered, and some examples are given. Our results can be applied to bubble chamber measurements of neutral particles, to counter experiments, for inclusive reactions as well as for exclusive ones.

What semi-inclusive data say about clusters

Our global analysis of inclusive high-energy multi-particle production data in the cluster model framework is extended to semi-inclusive data. Our cluster model embodies leading particle effects and kinematical constraints, which are shown to be of great importance. It appears that models with light clusters decaying on average into 〈n c 〉 ⋍ 2 charged particles, with a rapidity width δ ⋍ 0.6–0.7 and a distribution much narrower than a Poisson-type, allow one to fit in a nice way both inclusive and semi-inclusive data. It is pointed out that the most constraining semi-inclusive data are those regarding longitudinal correlations, which definitely exclude heavy cluster models, whereas the data on zone characteristics only bear out that a non-negligible percentage of clusters have to carry an electric charge.

Azimuthal correlations in high-energy multiparticle production

Some features of the two-particle correlation phenomena, studied by means of azimuthal angle variables, are discussed. Assuming Gaussian forms for the single transverse momentum distributions, it is proposed to described the two-particle correlation with only one parameter. The influence of the kinematical constraints on the proposed correlation parameter is discussed, using a limited transverse momentum phase-space model.

Hydrodynamical expansion with frame-independence symmetry in high-energy multiparticle production

We describe the space-time development of the hardronic system formed immediately after the high-energy hadron collision with the following picture. Initially the system is highly compressed along the longitudinal direction. The sudden relaxation of this compression leads to a violent acceleration along this direction and perhaps a weak acceleration along the transverse direction. When these accelerations cease, we propose that the system acquires certain frame-independence symmetry with its further expansion governed by the hydrodynamic equation of motion. Within our scheme, this symmetry provides a natural mechanism which eventually leads to a flat inclusive longitudinal rapidity distribution and it also admits a sharp cutoff in the inclusive transverse momentum distribution. These features differ from those of Landau's model.

On semi-inclusive rapidity correlations

A model-independent qualitative discussion on semi-inclusive rapidity correlations in high-energy multi-particle production processes is presented. Connection with previous results on the same subject are pointed out. Finally, one discusses semi-inclusive rapidity correlations in terms of reduced rapidities.

Cluster Mass Distribution in Multiperipheral Cluster Emission Model

It is shown that dynamics of the multiperipheral cluster em1ss1on model uniquely determines the cluster mass (M) distribution. In particular, the mass distribution is dynamically suppressed by the output factor (M')-Po(fi,>g'(p.), p.: final hadron mass) in addition to a possible decreasing effect due to the input factors of the cluster emission (g'(M)) and decay (JJ(M)) vertices. A dynamical equation for solving fio is derived. Some quantitative estimates are also presented. Since proposed in 1962 by ABFST,l> a multiperipheral model has been a continuing laboratory of physical interest when the multiple production of hadrons is studied. Incorporation of Regge exchanges 2>·8> along the multiperipheral chain makes the model more suitable for analyzing a high-energy multiparticle production. Quite recently, an idea that hadrons are produced in clusters 4> has provided a popular interpretation of several features of multiparticle production data. In particular, the postulates of (A) independent emission of clusters along th.e multiperipheral chain and (B) their isotropic decay via a Gaussian distribution in rapidity give a facile imitation of data on two-particle inclusive rapidity cor­ relations in the central regioit. 6> It is not clear whether clusters have any intrinsic dynamical significance (e.g., generalized resonances) or whether they are primarily of phenomenological convenience. Experimentally we still have to wajt for eve~t-by-event data on an exclusive rapidity distribution in order to observe directly the cluster formation and its detailed properties. On the other hand, the observed high multiplicity in rapidity space suggests that final hadrons should be produced more preferably through cluster (or resonance) formation along the multiperipheral chain to through factorized Regge exchanges between the final hadrons. It is a reasonable guess that due to a small average spacing of .dy~0.3 to 0.5 between the final hadrons, there will be a strong correlation among the produced particles, which is better represented by the above postulates (A) and (B). The purpose of this paper is to show that the postulates (A) and (B) just mentioned uniquely determine the mass distribution of produced clusters which is usually assumed to take a certain form as a third input. What is important, the predicted mass distribution can be checked experimentally when the exclusive

Proton-proton collisions in the hydrodynamic theory

Inspired by some earlier successes of Landau's hydrodynamic theory in explaining the data on high-energy multiparticle production in proton-proton collisions, we investigate exact formulas for the pion inclusive distribution in (1) the hydrodynamic theory, and (2) a statistical variant of this theory in which the thermal motion of the emitted particles is taken into account. All theoretical predictions of the exact spectra are without any free parameters. The results are (1) the exact spectra at Fermi National Accelerator Laboratory (FNAL) and CERN Intersecting Storage Rings energies are substantially broader than those obtained from the formula derived by Landau, (2) at $\sqrt{s}=52.8$ GeV the exact hydrodynamic theory gives a good description of the experimental data up to a center-of-mass rapidity of approximately 3, and (3) only Landau's original formula for the spectrum gives a satisfactory description of the FNAL data at $s\ensuremath{\simeq}565$ Ge${\mathrm{V}}^{2}$. We also obtain a formula for the average multiplicity without any adjustable parameter, and find that it gives an excellent description of the data above $s\ensuremath{\simeq}100$ Ge${\mathrm{V}}^{2}$.

Relations between Correlation Functions of Produced Particles and the Dynamics of High Energy Multi-Particle Production

Relations between Correlation Functions of Produced Particles and the Dynamics of High Energy Multi-Particle Production

Correlations Between Neutral and Charged Pions in Multiparticle Production

We investigate the dynamical significance of correlations between ${〈{n}_{0}〉}_{\ensuremath{-}}$ and ${n}_{\ensuremath{-}}$, where ${〈{n}_{0}〉}_{\ensuremath{-}}$ is the mean number of neutral pions observed in conjunction with ${n}_{\ensuremath{-}}$ negative tracks in high-energy multiparticle production processes. Several models are treated in turn. Pions are assumed to be produced either singly or in clusters, according to a Poisson or inverse-power distribution. Influences of charge, isospin, and energy-momentum conservation are studied. The linear rise of ${〈{n}_{0}〉}_{\ensuremath{-}}$ vs ${n}_{\ensuremath{-}}$ observed experimentally at very high energies is shown to rule out some models of multiperipheral type, but is in accord with fragmentation models and with a multiperipheral model in which $\ensuremath{\rho}$- or $\ensuremath{\omega}$-type meson clusters are emitted.

On high-energy multiparticle production and elastic-scattering processes

For many-particle production we study a model which assumes at fixed impact parameter a statistical picture of fireball formation and decay. We obtain in this way on the one hand for the usual statistical model an extension which includes angular-momentum conservation and allows predictions for all inelastic and corresponding absorptive elastic cross-sections, on the other a «central collision» counterpart of the peripheral model. The asymptotic predictions for production processes are discussed and compared to those of the usual statistical model and of the multiperipheral model. The resulting form for elastic and total cross-sections, obtained by unitarity, agrees with that given by Van Hove's uncorrelated particle model.