Study on the Resonant Parameters of Y (4220) and Y (4390)

Many vector charmonium-like states have been reported recently in the cross sections ofe +e - → ω χ c 0 ,π +π -h c ,π +π - J / ψ ,π +π - ψ ( 3686 ) , andπ +D 0D ⁎ - + c . c . To better understand the nature of these states, a combined fit is performed to these cross sections by using three resonances Y ( 4220 ) , Y ( 4390 ) , and Y ( 4660 ) . The resonant parameters for the three resonances are obtained. We emphasize that two resonances Y ( 4220 ) and Y ( 4390 ) are sufficient to explain these cross sections below 4.6 GeV. The lower limits of Y ( 4220 ) and Y ( 4390 ) ’s leptonic decay widths are also determined to be ( 36.4 ± 2.0 ± 4.2 ) and ( 123.8 ± 6.5 ± 9.0 ) eV.