Lattice QCD study of the heavy-heavy-light quark potential

We study the heavy-heavy-light quark (QQq) potential in SU(3) quenched lattice QCD, and discuss one of the roles of the finite-mass valence quark in the interquark potential. Monte Carlo simulations are performed with the standard gauge action on the 16(4) lattice at beta = 6.0 and the O(a)-improved Wilson fermion action at four hopping parameters. For statistical improvement, the gauge configuration is fixed with the Coulomb gauge. We calculate the potential energy of QQq systems as a function of the inter-heavy-quark distance R in the range of R <= 0.8 fm. The QQq potential is well described with a Coulomb plus linear potential, and the effective string tension between the two heavy quarks is significantly smaller than the string tension sigma similar or equal to 0.89 GeV/fm. It would generally hold that the effect of the finite-mass valence quark reduces the inter-two-quark confinement force in baryons.