Possible interpretation of the Zb(10610) and Zb(10650) in a chiral quark model

Abstract

Motivated by the two charged bottomonium-like resonances Zb(10610) and Zb(10650) newly observed by the Belle collaboration, the possible molecular states composed of a pair of heavy mesons, , etc (in S-wave), are investigated in the framework of chiral quark models by the Gaussian expansion method. The bound states and with quantum numbers I(JPC) = 1(1+−), which are good candidates for the Zb(10610) and Zb(10650), respectively, are obtained. Another three bound states with I(JPC) = 0(1++), with I(JPC) = 1(0++), 0(2++) are predicted. These states may be observed in an open-bottom or a hidden-bottom decay channel of highly excited ϒ. When directly extending the quark model to the hidden-color channel of the multi-quark system, more deeply bound states are found. Future experimental search of those states will cast doubt on the validity of applying the chiral constituent quark model to the hidden-color channel directly.