Relationship between constituent quark model and QCD -- Basic properties of the constituent quark

摘要

Experimental evidence shows that the fundamental objects in the quantum chromodynamics (QCD) are the current quarks which are manifest in the high energy process. On the other hand, the constituent quarks as effective degree of freedom have been verysuccessful in describing the hadron properties. The questions are: how do the constituent quarks relate to the QCD quarks? What are the general properties of the constituent quarks? These challenging problems have attracted many theoretical physicists, because they are very interesting and significant for understanding low-energy QCD, and so for improving the description of hadrons and their interactions. Although the relationship between the constituent quark mass and the QCD quark (current quark) masshas got a reasonable explanation, it is still a puzzle to understand why the effective coupling between the constituent quarks is much larger than the QCD coupling at the hadron mass scale, and to understand" the general properties of the constituent quarks such as their form factors and radii and so on.