On the spectrum of pure Yang-Mills theory
  In this note we discuss the wave functional approach to the spectrum of pure Yang-Mills theory in 2+1 and 3+1 dimensions by highlighting the issues of dynamical mass generation and the role played by the kinetic term. We extrapolate our recent analysis of 2+1 Yang-Mills theory to 3+1 dimensions, and under certain heuristic assumptions use a simple quasi-Gaussian vacuum wavefunctional for 3+1 Yang-Mills theory for a preliminary study of the spectrum of glueballs which nicely fits the available lattice simulations. 
Laurent Freidel, Robert G. Leigh, Djordje Minic and Alexandr Yelnikov