pt-Multiplicity Correlations in a Multi-Pomeron-Exchange Model with String Collective Effects

The < p(t)> (Nch)-N-ch correlations experimentally observed in the central rapidity region in pp and p (p) over bar collisions, in a wide energy range from the ISR to Tevatron, are described in the framework of a multi-Pomeron exchange model in which string collectivity has been included in an effective way. Three parameters are obtained from the fit to data: the string tension, the average number of particles per string, and a parameter which effectively introduces string collective effects. The model successfully reproduces the rise of < p(t)> of charged particles, the flattening with growing rapidity density of charged particles and with the collision energy, and the negative p(t)-N-ch correlation at low energies. The string tension and the average number of particles per string are energy independent, while the parameter that includes effectively string collective effects shows a smooth increasing behavior with energy.