On the invariant measure for the Yang-Mills configuration space in (3+1) dimensions

We consider a gauge-invariant Hamiltonian analysis for Yang-Mills theories in three spatial dimensions. The gauge potentials are parametrized in terms of a matrix variable which facilitates the elimination of the gauge degrees of freedom. We develop an approximate calculation of the volume element on the gauge-invariant configuration space. We also make a rough estimate of the ratio of $0^{++}$ glueball mass and the square root of string tension by comparison with $(2+1)$-dimensional Yang-Mills theory.