Meson and tetra-quark mixing

The mixing between qq̄ meson and qq̄qq̄ tetra-quark states is examined within an effective QCD Coulomb gauge Hamiltonian model. Mixing matrix elements of the Hamiltonian are computed and then diagonalized yielding an improved prediction for the low-lying J = 0, 1 isoscalar spectra. Mixing effects were found significant for the scalar hadrons but not for the 1 states, which is consistent with the ideal mixing of vector mesons. A perturbative assessment of the exact QCD kernel is also reported. PACS. 12.39.Mk Glueball and exotic multi-quark/gluon states – 12.39.Pn Potential models – 12.39.Ki Relativistic quark model – 12.40.Yx Hadron mass models and calculations