G. Berlad

Cumulative production of particles in high energy collisions

Abstract We show that the parton recombination model of hadron production combined with a quark-parton model of the nucleus describe cumulative meson production in high energy collisions with nuclei remarkably well.

Dominance of electromagnetic effects in high energy hadron and photon induced reaction

Abstract It is argued that at high enough energy the electromagnetic interaction will dominate over the strong interactions in all reactions that can proceed via photon exchange. Important consequences of this possibility are discussed. Among them are the possibility of measuring meson and photon structure functions already in the energy range of the NAL machine, the possibility of a breakdown of isospin invariance at high energy and its possible verification at the ISR CERN machine, and the inequality between particle and antiparticle cross sections at high energy.

Scaling Laws for Inclusive Production of Hadrons in High-Energy Particle-Nucleus Collisions

Simple scaling laws for inclusive production of hadrons in high-energy particle-nucleus collisions are derived from a model that has reproduced multiplicity distributions in high-energy particle-nucleus reactions. The success of the model, applied here to large-transverse-momentum reactions, suggests the possible use of nuclear targets and nuclear beams to investigate future energy domains of particle physics with present accelerators.

A LORENTZ INVARIANT FORMULATION OF VECTOR-MESON DOMINANCE IN PHOTOPRODUCTION.

The vector-meson dominance (VMD) for photoproduction is reformulated in a frame-independent way, by assuming weak dependence of the Poincare (ls) - reduced T matrix elements for the reaction “vector meson + target → hadrons” on the mass of the external vector meson. It then fellows that the T matrix elements for this reaction smoothly approach at high energy the corresponding matrix elements for the reaction “photon + target → hadrons”, provided the vector meson is transversely polarized in the s-channel c.m. frame. Some advantages of the new VMD formulation are pointed out, and some illustrative examples are explicitly studied.

Parton models and fragmentation of relativistic heavy ions

Abstract Parton models of particle fragmentation in high-energy particle collisions are extended to fragmentation of heavy ions into baryons and mesons in high-energy nuclear collisions. Good agreement between experiment and theory is demonstrated.

Photoproduction of pions and mass dependence of amplitudes

Abstract The validity of vector-meson dominance (VMD) relations for photoproduction of pseudoscalar mesons is tested in some well-defined calculable models. All models show that the production amplitudes of vector mesons transversely polarized in the s -channel helicity frame do not depend on the mass of the vector meson for large values of s , i.e. all models lead to the conclusion that the VMD relations for photoproduction should be postulated in the s -channel helicity frame. In particular this is true for the gauge invariant Born model incorporating exchange of particles with arbitrary spin and parity, and for the Van Hove model of reggeization, with or without absorption corrections.

Scaling laws for inclusive production of hadrons in high-energy particle-nucleus collisions. [Large transverse momentum]

Simple scaling laws for inclusive production of hadrons in high-energy particle-nucleus collisions are derived from a model that has reproduced multiplicity distributions in high-energy particle-nucleus reactions. The success of the model, applied here to large-transverse-momentum reactions, suggests the possible use of nuclear targets and nuclear beams to investigate future energy domains of particle physics with present accelerators.

Is the criticism of the tube model by Azimov et al. credible

Abstract We show that the paper “Is the Tube Approach to Multiple Production on Nuclei Credible?” by Azimov et al., misuses the Collective Tube Model (CTM), compares theoretical predictions with irrelevant experimental data while ignoring other relevant published experiments and consequently arrives at the wrong conclusions.

Inclusive production of hadrons in nucleus-nucleus collisions at high energies

SummaryA simple model for inelastic nucleus-nucleus collisions at high energies is proposed. Predictions are summarized in approximate, but simple, scaling laws that directly relate hadron production in high-energy nucleus-nucleus collisions to hadron production in high-energy nucleon-nucleon collisions. The possible use of nucleus-nucleus collisions to investigate future energy domains of particle physics with present accelerators is emphasized.RiassuntoSi propone un modello semplice per le collisioni anelastiche nucleo-nucleo ad alte energie. Si riassumono le predizioni in leggi di scala approssimate, ma semplici, che mettono direttamente in relazione la produzione di adroni in collisioni nucleo-nucleo ad alta energia con la produzione di adroni in collisioni nucleone-nucleone ad alta energia. Si pone l’accento sul possibile uso di collisioni nucleo-nucleo ad alta energia per studiare futuri domini dell’energia nella fisica delle particelle con i presenti acceleratori.РеэюмеПредлагается простая модель для неупругих соударений ядер с ядрами при высоких знергиях. Предскаэания сводятся к приближенным, но простым эаконам скейлинга, которые непосредственно свяэывают рождение адронов в соударениях ядер с ядрами при высоких знергиях с рождением адронов в нуклон-нуклонным соударениях при высоких знергиях. Обсуждается воэможность испольэования соударений ядер с ядрами для исследования будуших знергетических областей на сушествуюших ускорителях.

The phase and t-structure of exchange amplitudes. Application to reactions

Assuming asymptotic power-law behavior in energy for exchange amplitudes their phase is determined, using analyticity and crossing. The absence of exotic resonances is applied to fix the relations between even and odd amplitudes. Two qualitatively equivalent models are presented. The first one is based on simplicity and is found to resemble some Regge-pole-model interpretations. The second one results from a surface picture for exchange amplitudes. Within the general frame discussed here, the predictions of Regge-pole and absorption models become very similar. A qualitatively explanation for differential cross sections in 0−12+ → 0−12+, 0−32+ exchange reactions and for polarizations in elastic 0−12+ → 0−12+ processes is offered for |t| ⪅2.0 (GeV/c)2. Differences between Hararis recent approach and ours are discussed.