Toward finite zero-point energies in the bag model

Abstract

It is pointed out that the Casimir energies of noninteracting massless quark and gluon fields confined within spherical cavities are not quadratically divergent as previously stated but only logarithmically so. Since this residual weak surface divergence would be plausibly softened in a more realistic hadron model, the finite leading approximants should be fairly accurate. Per vector and Fermi degrees of freedom these are $E_v=\frac{0.072}{a}$ and $E_f=-\frac{0.0022}{a}$, where $a$ is the bag radius. Phenomenological implications are discussed.