Meson, baryon, and glueball masses in the MIT bag model

We present a consistent and unified study of the spectrum of low-lying mesons, baryons, and glueballs using the MIT bag model, incorporating several improvements in the model. We correct for the center-of-mass motion, use a running coupling ${\ensuremath{\alpha}}_{s}(R)$, include self-energy terms for quarks and gluons confined in a cavity, and get the bag constant from a model of the QCD vacuum. Our fit to the meson and baryon spectrum, including the pion, is good and predictions for the glueball spectrum are given.