Measurement of parameters

Abstract: We report the final results of a study of the meson using a data sample collected with the KEDR detector at the VEPP-4M electron–positron collider. The data analysis takes into account interference between the resonant and nonresonant production, where the latter is related to the nonresonant part of the energy-dependent form factor . The vector dominance approach and several empirical parameterizations have been tried for the nonresonant . Our results for the mass and total width of are where the first, second and third uncertainties are statistical, systematic and model, respectively. For the electron partial width two possible solutions have been found: Our statistics are insufficient to prefer one solution to another. The Solution (2) mitigates the problem of non- decays but is disfavored by potential models. It is shown that taking into account the resonance–continuum interference in the near-threshold region affects resonance parameters, thus the results presented cannot be directly compared with the corresponding PDG values obtained ignoring this effect. [Copyright &y& Elsevier]