Title of article :
S-matrix unitarity, impact parameter profiles, gluon saturation and high-energy scattering
Original Research Article
Author/Authors :
A.I. Shoshi، نويسنده , , F.D. Steffen، نويسنده , , H.J. Pirner، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2002
Abstract :
A model combining perturbative and non-perturbative QCD is developed to compute high-energy reactions of hadrons and photons and to investigate saturation effects that manifest the S-matrix unitarity. Following a functional integral approach, the S-matrix factorizes into light-cone wave functions and the universal amplitude for the scattering of two color-dipoles which are represented by Wegner–Wilson loops. In the framework of the non-perturbative stochastic vacuum model of QCD supplemented by perturbative gluon exchange, the loop–loop correlation is calculated and related to lattice QCD investigations. With a universal energy dependence motivated by the two-pomeron (soft + hard) picture that respects the unitarity condition in impact parameter space, a unified description of pp, πp, Kp, γ∗p, and γγ reactions is achieved in good agreement with experimental data for cross sections, slope parameters, and structure functions. Impact parameter profiles for pp and View the MathML source reactions and the gluon distribution of the proton View the MathML source are calculated and found to saturate in accordance with S-matrix unitarity. The c.m. energies and Bjorken x at which saturation sets in are determined.
Keywords :
Gluon saturation , Loop-loop scattering , High-energy scattering , Multiple-gluon exchange , Pomeron , QCD , Unitarity , Stochastic vacuum model , Impact parameter profiles
Journal title :
Nuclear physics A
Journal title :
Nuclear physics A