Self-Consistent Quark Bags

Abstract

We do not understand the forces that keep the quarks (semi-) permanently bound in hadrons. The known experimental properties of quark bound states — hadrons — appear self-contradictory, when confronted with our past experience with nuclear and atomic physics. The basic problem is that experimental information indicates that hadronic properties are well described in a model of weakly interacting (quasi) particles. A possible solution to this dilemma, on which we base our investigations, is a model¹⁾ in which the bound state of a few heavy particles²⁾ is viewed as a collection of quasi-particles of relatively small mass, each moving in an average “shell” potential independently of the others. It is only when we forcefully destroy this hadronic “bag” that the true nature of the underlying very massive fields becomes more apparent — but with no free quarks escaping from the region of the interaction. In this picture there are two possibilities to view the absence of asymptotically free quark states: either their free mass is still higher than presently available energies m_q ≳ 10 GeV, or their decay width is very high²⁾. In the latter case it is necessary to consider quarks as quantities with integral quantum numbers.