Nonstrange quark mass in the bag model

Abstract

The MIT bag model of the nucleon is extended to include the effect of finite nonstrange quark mass. If the nucleon axial-vector coupling constant is used to fix the quark mass, then using $g_A=1.25\mathrm{}$ we find $m=122\mathrm{}$ MeV for the mass of the degenerate up and down quarks. Other attributes of the nucleon are evaluated in this model and the limiting case of infinite quark mass is studied as a check on the calculation.