We study the meson-meson and meson-baryon interactions in lattice QCD. The simulation is performed on 20^3 * 24 lattice at ��=5.7 using Wilson gauge action and Wilson fermion at the quenched level. By adopting one static quark for each hadron as "heavy-light meson" and "heavy-light-light baryon", we define the distance $r$ of two hadrons and extract the inter-hadron potential from the energy difference of the two-particle state and its asymptotic state. We find that both of the meson-meson and meson-baryon potentials are nontrivially weak for the whole range of 0.2 fm <= r <= 0.8 fm. The effect of including/excluding the quark-exchange diagrams is found to be marginal.

Talk given at Particles and Nuclei International Conference (PANIC05), Santa Fe, NM, USA, 24-28 Oct. 2005. 3 pages, 2 figures