Geometric Scaling and QCD Dynamics in DIS
نویسنده
چکیده
DIS data from HERA show a striking regularity as σγ p is a function of the ratio τ = Q/Qs(x) only. The scaling function shows a break at τ ≈ 1, which has been taken as an indication for saturation. However, besides saturation also the transition between dominance of k⊥-ordered (DGLAP) and k⊥-non-ordered (BFKL) evolution contributes to a break around this value of τ , as well as the suppression for small Q2 due to finite quark masses and confinement. In this paper we use a dipole cascade model based on Mueller’s dipole model, which also includes energy conservation and pomeron mergings, to investigate the contributions of these different effects to the scaling behaviour. As a result we predict that the scaling function for τ < 1 will be modified when data for Q2 > 1GeV become available. We also investigate the scaling properties of the charm contribution and the impact parameter dependence of the saturation scale.
منابع مشابه
Small-x neutrino-hadron structure functions in charged current DIS within the QCD color dipole picture
We present an exploratory QCD analysis of the neutrino structure functions in charged current DIS using the color dipole formalism. The corresponding dipole cross sections are taken from recent phenomenological/theoretical studies in deep inelastic inclusive production. The theoretical predictions are compared to the available experimental results in the small-x region. In particular, the behav...
متن کاملIn the Shadow of the Color Glass *
I give a brief overview of recent theoretical progress within perturbative QCD concerning the high–energy dynamics in the vicinity of the unitarity limit. Special attention is payed to the most recent developments concerning the relation between high–energy QCD and statistical physics, the role of the pomeron loops, and the transition from geometric scaling to diffusive scaling with increasing ...
متن کاملGeometric scaling in inclusive eA reactions and nonlinear perturbative QCD.
We report on geometric scaling in inclusive eA scattering data from the NMC and E665 experiments. This scaling and nuclear shadowing follows the pattern expected from nonlinear perturbative QCD for zero impact parameter at sufficiently small x(bj) and is compatible with geometric scaling in ep.
متن کاملResummation in Transversely Polarized Drell - Yan Process
Hard processes with polarized nucleon beams enable us to study spin-dependent dynamics of QCD and the spin structure of nucleon. The helicity distribution ∆q(x) of quarks within nucleon has been measured in polarized DIS experiments, and ∆G(x) of gluons has also been estimated from the scaling violations of them. On the other hand, the transversity distribution δq(x), i.e. the distribution of t...
متن کاملSaturation and geometric scaling in DIS at small x
We present various aspects of the saturation model which provides good description of inclusive and diffractive DIS at small x. The model uses parton saturation ideas to take into account unitarity requirements. A new scaling predicted by the model in the small x domain is successfully confronted with the data.
متن کامل