ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2012, vol. 711, p. 292-300
Measurement of ψ(3770) parameters
We report the final results of a study of the ψ(3770) 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 DD - production, where the latter is related to the nonresonant part of the energy-dependent form factor F D. The vector dominance approach and several empirical parameterizations have been tried for the nonresonant FDNR(s).Our results for the mass and total width of ψ(3770) are. M=3779.2-1.7+1.8-0.7+0.5-0.3+0.3MeV,Γ=24.9-4.0+4.6-0.6+0.5-0.9+0.2MeV, where the first, second and third uncertainties are statistical, systematic and model, respectively. For the electron partial width two possible solutions have been found:. (1)Γee=154-58+79-9+17-25+13eV,(2)Γee=414-80+72-26+24-10+90eV. Our statistics are insufficient to prefer one solution to another. The Solution (2) mitigates the problem of non-. DD - 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. © 2012.