Systematics of leading particle production

Abstract

Using a QCD-inspired model developed by our group for particle production, the interacting gluon model ͑IGM͒, we have made a systematic analysis of all available data on leading particle spectra. These data include diffractive collisions and photoproduction at DESY HERA. With a small number of parameters ͑essentially only the nonperturbative gluon-gluon cross section and the fraction of diffractive events͒ good agreement with data is found. We show that the difference between pion and proton leading spectra is due to their different gluon distributions. We predict a universality in the diffractive leading particle spectra in the large momentum region, which turns out to be independent of the incident energy and of the projectile type.

The Interacting Gluon Model: a review

“…Its original application to the description of inelasticity [12] and multiparticle production processes in hydrodynamical treatments [13] was followed by more refined applications to leading charm production [14] and to single diffraction dissociation, both in hadronic reactions [15] and in reactions originated by photons [16]. These works allowed for providing the systematic description of the leading particle spectra [17] and clearly demonstrated that they are very sensitive to the amount of gluonic component in the diffracted hadron as observed in [18] and [19]. We have found it remarkable that all the results above were obtained using the same set of basic parameters with differences arising essentially only because of the different kinematical limits present in each particular application.…”

Extracting the Pomeron-Pomeron cross section from diffractive mass spectra

“…The IGM has been described at length, especially in [7] and more recently in [11]. In the past we have successfully modified the IGM in such way as to include in it hadronic single diffractive dissociation processes [9][10][11][12] and applied it to hadronic collisions and HERAphotoproduction data (M 2 X distributions and leading particles spectra of p, π, K and J/ψ).…”

“…In what follows, we briefly mention our main formulas. For further discussion we refer to the works [9][10][11].…”

“…According to the IGM [11], the probability to form a fireball carrying momentum fractions x and y of two colliding hadrons (see Fig. 1) is given by:…”

“…In the past we have successfully modified the IGM in such way as to include in it hadronic single diffractive dissociation processes [9][10][11][12] and applied it to hadronic collisions and HERAphotoproduction data (M 2 X distributions and leading particles spectra of p, π, K and J/ψ). The main idea of the model is that nucleon-nucleon collisions at high energies can be treated as an incoherent sum of multiple gluon-gluon collisions, the valence quarks playing a secondary role in particle production.…”