Gluonic-excitation energies and Abelian dominance in SU(3) QCD

We present the first study of the Abelian-projected gluonic-excitation energies for the static quarkantiquark (Q (Q) over bar) system in SU(3) lattice QCD at the quenched level, using a 32(4) lattice at beta = 6.0. We investigate ground-state and three excited-state Q (Q) over bar potentials, using smeared link variables on the lattice. We find universal Abelian dominance for the quark confinement force of the excited-state Q (Q) over bar potentials as well as the ground-state potential. Remarkably, in spite of the excitation phenomenon in QCD, we find Abelian dominance for the first gluonic-excitation energy of about 1 GeV at long distances in the maximally Abelian gauge. On the other hand, no Abelian dominance is observed for higher gluonic-excitation energies even at long distances. This suggests that there is some threshold between 1 and 2 GeV for the applicable excitation-energy region of Abelian dominance. Also, we find that Abelian projection significantly reduces the short-distance 1=r-like behavior in gluonic-excitation energies.