Unquenching the Quark Model

Abstract

The formalism for a new generation of unquenched quark models for baryons in which the effects of quark–antiquark pairs are taken into account in an explicit form via a microscopic, QCD-inspired, quark–antiquark creation mechanism, is presented. As an application the quark–antiquark contribution to the spin of the proton and the Σ+ is discussed. Finally the strangeness radius of the Σ+ in the closure limit is calculated.