Investigating tetraquarks composed of usbar{d}bar{b} and udbar{s}bar{b}

Abstract

In the framework of the quark delocalization color screening model, we investigate tetraquarks composed of usbar{d}bar{b} and udbar{s}bar{b} in two structures: meson-meson structure and diquark–antidiquark structure. Neither bound state nor resonance state is found in the system composed of usbar{d}bar{b}. The reported X(5568) cannot be explained as a molecular state or a diquark–antidiquark resonance of usbar{d}bar{b} in present calculation. However, two bound states of the diquark–antidiquark structure are obtained in the tetraquarks system composed of udbar{s}bar{b}: an IJ=00 state with the mass of 5701 MeV, and an IJ=01 state with the mass of 5756 MeV, which maybe the better tetraquark states with four different flavors. Our results indicate that the diquark–antidiquark configuration would be a good choice for the tetraquarks udbar{s}bar{b} with quantum numbers IJ=00 and IJ=01. The tetraquarks composed of udbar{s}bar{b} is more possible to form bound states than the one composed of usbar{d}bar{b}. These bound states are worth investigating in future experiments.