We give the results of a simple model for the diagonal and off-diagonal valence quark distributions of a pion. We show that structure can be implemented in a gauge-invariant manner. This explicit model questions the validity of the momentum sum rule, and gives an explicit counter-example to the WandzuraWilczek ansatz for twist-3 GPD’s.

The soft production problem in hadronic collisions as described in the eikonal color mutation branching model is improved in the way that the initial parton distribution is treated. Furry branching of the partons is considered as a means of describing the nonperturbative process of parton reproduction in soft interaction. The values of all the moments, 〈n〉 and Cq, for q = 2, · · · , 5, as well ...

Using a multiphase transport model, we study J/c production from interactions between charm and anticharm quarks in the initial parton phase and between D and D̄ mesons in the final hadron phase of relativistic heavy ion collisions at the relativistic heavy ion collider. Including also the inverse reactions of J/c absorption by gluons and light mesons, we find that the net number of J/c from the...

Multiple parton scatterings inside a large nucleus generally involve highertwist nuclear parton matrix elements. The gluon bremsstrahlung induced by multiple scattering depends not only on direct parton matrix elements but also on momentum-crossed ones, due to the Landau-Pomeranchuk-Migdal interference effect. We show that both types of twist-four nuclear parton matrix elements can be factorize...