Vortex free energies in SO(3) and SU(2) lattice gauge theory
  Lattice gauge theories with gauge groups SO(3) and SU(2) are compared. The free energy of electric twist, an order parameter for the confinement-deconfinement transition which does not rely on centre-symmetry breaking, is measured in both theories. The results are used to calibrate the scale in SO(3). 
Philippe de Forcrand and Oliver Jahn