The motion of quark is studied in a confining bag having central color field. The Dirac equation is solved for a quark in such bag and its energy spectrum is found. It is pointed out the possibility to take into account an interaction of constituent quark with the gluon condensation as the interaction with the color background.

We study a parton shower description, based on a dipole picture, of the final state in electron-positron annihilation. In such a shower, the distribution function describing the inclusive probability to find a quark with a given energy depends on the shower evolution time. Starting from the exclusive evolution equation for the shower, we derive an equation for the evolution of the inclusive qua...

We argue that there is strong experimental evidence in the data of band c-decays that the pattern of power suppressed corrections predicted by the short distance expansion, the heavy quark effective theory and the assumption of local duality is not correct for the non-leptonic inclusive widths. The data indicate instead the presence of 1/m corrections that should be absent in the above theoreti...

We review the present status of theoretical predictions for both closed (J/ψ) and open heavy quark production in high energy collisions, and their comparisons to experimental data.

This talk summarizes recent progress in top quark physics studies for high energy linear electron-positron colliders as presented at the LCWS2000 Workshop at Fermilab. New results were presented for top pair production at threshold and in the continuum, as well as for top production at γγ colliders.

The transverse polarization (or transversity) distributions ∆T q(x), introduced 20 years ago by Ralston and Soper [1] and studied in more detail in the last decade [2], are one of the three sets of leading-twist quark and antiquark distribution functions – the other two are the momentum distributions q(x) and the helicity distributions ∆q(x). (Note that ∆T q is often called h1). Formally ∆T q i...