Vector decay constants in quarkonia
  Lattice NRQCD with leading finite lattice spacing errors removed is used to simulate heavy-heavy vector decay constants. Quenched simulations are performed at three values of the coupling and fifteen values of the quark mass. The improved gauge action with plaquettes and rectangles is used. Landau link improvement is used throughout. "Perturbative" and nonperturbative meson masses are compared. One-loop perturbative matching between lattice and continuum heavy-heavy vector currents is performed. The data is consistent with the vector meson decay constant being proportional to the square root of its mass. 
B. D. Jones and R. M. Woloshyn (TRIUMF)