TENSOR COUPLING OF THE RHO-MESON IN A CHIRAL CONFINING MODEL

Both the field current identity and universal coupling imply that the isovector part of the anomalous magnetic moment of the nucleon, v, is equal to the tensor coupling of the meson. However, the empirical value of extracted through dispersion relation is 1.78. In this paper we show that a color dielectric model can explain in a natural way why the ratio v>1. We study a chirally invariant color dielectric model. We point out that a fractional power of the color dielectric function should be present in the quark-meson interaction term. The quark part of the meson current, modified by this factor, is structurally different from the isovector part of the electromagnetic current. Both the magnetic-moment-like quantity, and the -nucleon coupling constant, gNN, are modified making =(()p-()n)(2M/gNN)-1 different from v and, indeed, larger than v. The numerical value of the ratio v is found to be 1.35, quite independent of the details of the model. It appears that some additional mechanism is needed to fit the value 1.78. © 1990 The American Physical Society.