QUARK-QUARK CORRELATIONS IN THE NUCLEON IN A GENERALIZED NAMBU-JONA-LASINIO MODEL

We present a relativistic model of the nucleon based upon a quark-diqu ark structure that emerges from a study of the Nambu-Jona-Lasinio mode l. Similar calculations, made by other authors, have been carried out after a Wick rotation is performed. These previous calculations have n eglected confinement; therefore, the masses of the quarks and diquarks had to be adjusted so that the diquarks and the nucleon were stable, in which case the Wick rotation may be made. In our work, we include a momentum-space model of confinement developed earlier and we are ther efore able to carry out the calculation in Minkowski space, after maki ng a number of approximations. We determine the relative admixture of a scalar-isoscalar diquark and an axialvector-isovector diquark dynami cally and find that an approximately equal admixture provides a reason able fit to the nucleon magnetic moments. While the original problem ( without approximation) requires the specification of eight scalar func tions of two variables, our various approximations allow us to calcula te several functions of a single variable. We find that only two of th ese functions are important. Therefore, we can exhibit a relatively si mple relativistic wave function of the nucleon expressed in terms of t wo wave functions describing the relative motion of the quarks and diq uarks.