P t -Multiplicity correlations in a multi-pomeron-exchange model with string collective effects

Abstract

The 〈pt〉Nch - Nch correlations experimentally observed in the central rapidity region in pp and p\( \bar p \) 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 〈pt〉 of charged particles, the flattening with growing rapidity density of charged particles and with the collision energy, and the negative pt-Nch 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.