Recent experimental measurements of high pT hadron spectra and jet correlation at RHIC are analyzed within a parton model which incoporates initial jet production and final propagation in heavy-ion collisions. The suppresion of single hadron spectra, back-to-back correlation, their centrality dependence and azimuthal anisotropy point to a dense matter with an initial parton density about 30 tim...

Radiatively generated, LO quark (u, d, s, c, b) and gluon densities in the real, unpolarized photon, calculated in the CJK model being an improved realization of the CJKL approach, have been recently presented. The results were obtained through a global fit to the experimental F γ 2 (x,Q 2) data. In this paper we present, obtained for the very first time in the photon case, an estimate of the u...

We analyze the impact-parameter dependent diagonal non-singlet generalized parton distribution of the pion in two distinct chiral quark models: the Spectral Quark Model and the Nambu-Jona-Lasinio model. Leading-order perturbative QCD evolution from the low quark-model scale to higher scales is carried out with the help of the inverse Mellin transform. The model agrees very reasonably with the r...

The scaling behavior of deep inelastic single-particle inclusive electroproduction (or neutrino production) expected from the parton model has been given by Drell and Yan as v 3 g&2 when the observed hadron has a finite fraction of the virtual photon’s laboratory momentum. Although Drell and Yan give the correct scaling behavior with their choice of variables, we show that with variables more a...

The Weisberger relation, an exact statement of the parton model, elegantly relates a high-energy physics observable, the 1/x moment of parton distribution functions, to a nonperturbative low-energy observable: the dependence of the nucleon mass on the value of the quark mass or its corresponding quark condensate. We show that contemporary fits to nucleon structure functions fail to determine th...

It is pointed out that, in contrast to the recently discovered large QCD correction to the Drell-Yan formula, a certain quark-parton model relation between structure functions for lepton pair production is not subject to any first order QCD modification. Both parallelism and contrast to the Callan-Gross relation in deep inelastic scattering are spelled out. Implications on the lepton angular di...

We present a phenomenological approach (EPOS), based on the parton model, but going much beyond, and try to understand proton-proton and deuteron-gold collisions, in particular the transverse momentum results from all the four RHIC experiments. It turns out that elastic and inelastic parton ladder splitting is the key issue. Elastic splitting is in fact related to screening and saturation, but ...