Resonances in J/ψ → φπ+π- and φK+K-

A partial wave analysis is presented of J/psi --> phipi(+)pi(-) and phiK(+)K(-) from a sample of 58M J/psi events in the BES II detector. The f(0)(980) is observed clearly in both sets of data, and parameters of the Flatte formula are determined accurately: M = 965 +/- 8(stat) +/- 6(syst) MeV/c(2), g(1) = 165 +/- 10 +/- 15 MeV/c(2), g(2)/g(1) = 4.21 +/- 0.25 +/- 0.21. The phipipi data also exhibit a strong pipi peak centred at M = 1335 MeV/c(2). It may be fitted with f(2)(1270) and a dominant 0(+) signal made from f(0)(1370) interfering with a smaller f(0)(1500) component. There is evidence that the f(0)(1370) signal is resonant, from interference with f(2)(1270). There is also a state in pipi with M = 1790(-30)(+40) MeV/c(2) and Gamma = 270(-30)(+60) MeV/c(2); spin 0 is preferred over spin 2. This state, f(0)(1790), is distinct from f(0)(1710). The phiK (K) over bar data contain a strong peak due to f(2)'(1525). A shoulder on its upper side may be fitted by interference between f(0)(1500) and f(0)(1710). (C) 2004 Elsevier B.V. All rights reserved.