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 [cq][(c) over bar(q) over bar] (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 [cq][(c) over bar(q) over bar] with n(2S+1)L(J) of 1(1)P(1,) 1(5)P(1,) 2(1)P(1) and 1(5)F(1), respectively, in the color flux-tube model. They are compact three-dimensional spatial configurations similar to a rugby ball, higher orbital angular momentum.., 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.