First observation of three pseudoscalar states in J/psi. --> gamma. rhorho decay

The Jpsi..--> gamma pi../sup +/..pi../sup -/..pi../sup +/..pi../sup -/ and J/psi..--> gamma pi../sup +/..pi../sup -/..pi../sup 0/..pi../sup 0/ decays have been studied by the DM2 experiment from 8.6 x 10/sup 6/ J/psi's. Both decays exhibit a large pseudoscalar rhorho dynamics. Three J/sup P//sup C/ = 0/sup -+/ resonant states (more than 3500 events, globally) decaying into rho/sup 0/rho/sup 0/ and with less statistical significance into rho/sup +/rho/sup -/ are observed. Their branching ratios into rho/sup 0/rho/sup 0/ and rho/sup +/rho/sup -/ support an I/sup G/ = 0/sup +/ assignment. These states, named eta(1500), eta(1800), and eta(2100), are not associated with well-established resonances.