Identification of Y(4008), Y(4140), Y(4260), and Y(4360) as Tetraquark States

Within the framework of a color flux-tube model with a four-body confinement potential, the tetraquark states cqcq (q=u or d) with IJ^PC=01^– are systematically investigated. The numerical results indicate that states Y(4008), Y(4140), Y(4260), and Y(4360) can be uniformly described as tetraquark states cqcq with n^2S+1L_J of 1¹P₁, 1⁵P₁, 2⁵P₁ and 1⁵F₁, respectively, in the color flux-tube model. They are compact three-dimensional spatial configurations similar to a rugby ball, higher orbital angular momentum L, more prolate. The four-body confinement interaction based on a color flux-tube picture should be responsible for the formation of those compact tetraquark states.