Semihard QCD and high-energyppandp¯pscattering

Abstract

We present the results of an analysis of high-energy pp and pp scattering based on a model in which the energy dependence of very-high-energy processes is driven by semihard scatterings of quarks and gluons in the nucleons. We show in particular that parton-parton scattering processes at small x drive not only the observed increases in total, elastic-, and inelastic-scattering cross sections and the forward slope parameter, but also, through analyticity, a rapid increase in the ratio of the real to the imaginary part of the forward elastic-scattering amplitude. We also give a careful definition of the inclusive jet cross section and present results on a,,,, average jet multiplicities, and jet-multiplicity fluctuations at high energies.

A quantitative investigation of the pomeron

“…Accordingly, the growth of the cross section associated with the soft Pomeron is attributed mostly to a blackening of the b-space scattering amplitude. This property is common to many other models [9,16]. The b-space characteristics of the Lipatov Pomeron are less clear.…”

“…Finally, we have also examined the possibility that the increase of σ tot with increasing s is connected to the onset of minijets produced by parton-parton collisons at energies above the ISR region [16]. In such a model the b-space transform of G 2 (t) is normalized by the hard parton-parton cross sections to which we also add a soft background.…”

“…In such a model the b-space transform of G 2 (t) is normalized by the hard parton-parton cross sections to which we also add a soft background. We disregard the fact that the various authors of reference [16] actually calculated an inclusive rather than a total cross section, and examine the generic form…”

Photoproduction total cross section and shower development

“…The large errors affecting the cosmic ray experimental data had cast uncertainty on a definite conclusion, but the ISR measurements definitively confirmed the rise, which was soon interpreted as a clear indication of the composite parton picture we are familiar with today. The role of mini-jets both in minimum bias physics [13] and in the rise of the total cross section [14] was then further developed and is input to many simulation programs.…”

p – airproduction cross-section and uncorrelated mini-jets processes in pp-scattering

“…Since the '80s, many models have used mini-jets in total cross-section physics [15][16][17] and more recently in [18]. In most cases, the parton density functions [PDFs] are chosen or parametrized ad hoc.…”