The SU(2) gluonic correlation functions, glueball effective masses in the $J^{ P}=0^{ +}$, $2^{ +}$ and $0^{ -}$ channels were calculated from the lattice classical gauge configurations which were obtained by smoothing the thermal gauge configurations through the improved cooling method. The instanton-induced attractive force in the $0^{ +}$ channel and the repulsive force in the $0^-$ channel are confirmed in the Monte Carlo simulation. There is evidence that the instanton vacuum contribution to the $0^+$ glueball mass is significant.
Categories: hep-lat