Utilizing the generalized factorization of twist-4 processes, we derive the modified heavy quark fragmentation function after considering the gluon radiation induced by multiple scattering in DIS. It is found that the mass effects of heavy quark may reduce the gluon formation time and change the medium size dependence of heavy quark energy loss. The radiative energy loss is also significantly s...

The scattering of a baryon consisting of three massive quarks is investigated in the high energy limit of perturbative QCD. A model of a relativistic proton-like wave function, dependent on valence quark longitudinal and transverse momenta and on quark helicities, is proposed, and we derive the baryon impact factors for two, three and four t-channel gluons. We find that the baryonic impact fact...

We discuss the high energy photodisintegrataion of light nuclei in which the energy of the absorbed photon is equally shared between two nucleons in the target. For these reactions we investigate the model in which photon absorption by a quark in one nucleon followed by its high momentum transfer interaction with a quark of the other nucleon leads to the production of two nucleons with high rel...

1 Abstract Lattice QCD calculation of s-wave hadron scattering lengths in the channels π-π, π-N, K-N, ¯ K-N and N-N is carried out in the quenched approximation at β = 6/g 2 = 5.7. A variant of the method of wall source is developed for this purpose, which reduces the computer time by a factor L 3 on an L 3 × T lattice compared to the conventional point source method and avoids the Fierz mixing...

Multiple scattering, modified fragmentation functions, and radiative energy loss of a heavy-quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy-quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased...

The HERMES experiment has studied for more than a decade deep-inelastic scattering of electrons/positrons from longitudinally and transversely polarised and also unpolarised atomic gas targets internal to the electron storage ring of HERA. The collected semi-inclusive data allowed to extract informations about various quark distribution and fragmentation functions. Examples presented in this co...