We propose a measurement on the elastic ππ scattering phase shift difference δ00−δ02 through Ψ′→J/Ψπ+π− process in future high statistics BES-III experiment. The decay amplitude is constructed with seven Lorentz invariant form-factors and is compared with their theoretical estimation. It is found that the phase shift difference can be obtained, based on a Monte Carlo study and it is expected the phase shift in the energy region between 350 MeV to 550 MeV can be measured at future BES-III.
@article{arxiv.0805.2780,
title = {Studies on $\pi^+\pi^-$ phase motion in the $\Psi'\to J/\Psi \pi^+ \pi^-$ process},
author = {Z. X. Zhang and J. J. Sanz-Cillero and X. Y. Shen and N. Wu and L. Y. Xiao and H. Q. Zheng},
journal= {arXiv preprint arXiv:0805.2780},
year = {2008}
}