  We use a hybrid Monte Carlo algorithm in which a single-cluster update is
combined with the over-relaxation and Metropolis spin re-orientation algorithm.
Periodic boundary conditions were applied in all directions. We have calculated
the fourth-order cumulant in finite size lattices using the single-histogram
re-weighting method. Using finite-size scaling theory, we obtained the critical
temperature which is very different from that of the usual XY model. At the
critical temperature, we calculated the susceptibility and the magnetization on
lattices of size up to $42^3$. Using finite-size scaling theory we accurately
determine the critical exponents of the model and find that $\nu$=0.670(7),
$\gamma/\nu$=1.9696(37), and $\beta/\nu$=0.515(2). Thus, we conclude that the
model belongs to the same universality class with the XY model, as expected.
