New Analysis of J/psi Decays into a Vector Meson and Two Pseudoscalars

Recently, the BES collaboration has published an extensive partial wave analysis of experimental data on J/psi -> phi pi+pi-, J/psi -> omega pi^+pi^-, J/psi -> phi K+K- and J/psi -> omega K+K-. These new results are analyzed here, with full account of detection efficiencies, in the framework of a chiral unitary description with coupled-channel final state interactions between pi-pi and K-Kbar pairs. The emission of a dimeson pair is described in terms of the strange and non-strange scalar form factors of the pion and the kaon, which include the final state interaction and are constrained by unitarity and by matching to the next-to-leading-order chiral expressions. This procedure allows for a calculation of the S-wave component of the dimeson spectrum including the f_0(980) resonance, and for an estimation of the low-energy constants of Chiral Perturbation Theory, in particular the large N_c suppressed constants L_4^r and L_6^r. The decays in question are also sensitive to physics associated with OZI violation in the 0++ channel. It is found that the S-wave contributions to phi pi+pi-, phi K+K- and omega pi+pi- given by the BES partial-wave analysis may be very well fitted up to a dimeson center-of-mass energy of 1.2 GeV, for a large and positive value of L_4^r and a value of L_6^r compatible with zero. An accurate determination of the amount of OZI violation in the J/psi -> phi pi+pi- decay is achieved, and the S-wave contribution to omega K+K- near threshold is predicted