Nonlinear effects and the behavior of total hadronic and photonic cross sections

Abstract

In this paper we use an eikonalized minijet model where the effects of the first nonlinear corrections to the DGLAP equations are taken into account. The contributions coming from gluon recombination effects are included in the DGLAP þ GLRMQ approach for the free proton in the context of saturation models. The parameters of the model are fixed to fit total pp and "pp cross sections, including the very recent data from LHC, HiRes, and Pierre Auger collaborations. Glauber and multiple scattering approximations are then used to describe the inclusive inelastic proton-Air cross section. Photoproduction cross sections, without change of parameters fixed before, are also obtained from the model using vector meson dominance and the additive quark model. We show and discuss our main results as well as the implications of saturation effects in the behavior of total hadronic and photonic cross sections at very high energies.

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

“…The result is shown in Fig. 3 where our model is compared with cosmic ray data [9,[37][38][39][40][41][42][43] and with two other mini-jet models, a recent one [18] and the first such application by Durand and Pi [15]. We notice that the old model is rather above the cosmic ray data point, as they are presently extracted.…”

“…The two curves from the BN model (full and dashes) are obtained with a different low energy constant, σ 0 . The results from the mini-jet model of [18] is given by the dotted curve. The dashed curve is the first mini-jet application of a mini-jet model for cosmic ray cross-section, from [15].…”

“…2 shows also the mini-jet result Ref. [18], where a different set of PDFs is used, and a different impact parameter distribution. The mini-jet contributions in these two applications of the mini-jet model are different, but both are based on a single-channel eikonal approach.…”

“…The determination of the optimal model parameters was done in-dependently of the AUGER data. The dotted curve is from the mini-jet model of [18].Accelerator data at LHC include TOTEM [29,30] and ATLAS [31] measurements.The inelastic uncorrelated crosssection is given by the dashed curve and compared with central collisions results at LHC by ATLAS [32], CMS [33] and ALICE [34].…”

“…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.…”