HYBRIDS AND QUARK CONFINEMENT

It has become traditional to assume that the Dirac structure of the ph enomenological quark confinement potential is scalar x scalar. We use the heavy quark expansion of the Coulomb gauge QCD Hamiltonian and the Flux Tube model to demonstrate that this is true but in the effective sense only. The demonstration contains some surprises: confinement is actually vector x vector and it is nonperturbative mixing between ord inary and hybrid <Q(Q)over bar> states which generates the scalar-like spin dependent potential at order 1/m(q)(2). Thus the existence of hy brids is crucial to establishing well-known spin splitting phenomenolo gy. Finally, the resolution also indicates that the gluonic degrees of freedom in a hybrid must be of a collective nature.