Studies on $π^+π^-$ phase motion in the $Ψ'\to J/Ψπ^+ π^-$ process

Abstract

We propose a measurement on the elastic $ππ$ scattering phase shift difference $δ^0_0-δ^2_0$ through $Ψ'\to J/Ψπ^+ π^-$ 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.

16 pages, 1 figure