Rescattering effect in J/Psi(Psi') to 3 pi decay and rho-pi puzzle

Peng Guo
Indiana University

It is suggested that final state interaction may play important role in 
rho - pi puzzle.  In this work, we propose and investigate  corrections 
to naive isobar model from three body rescattering effect in 
J/Psi(Psi') --> 3 pi channels. By taking into account constraints from  
unitarity and analyticity, a set of coupled single variable integral 
equations about three-body amplitudes are derived from dispersion 
relation,  and they are suitable  for  numerical evaluation  and 
experimental data fitting.  We conclude that the long distance final 
state interaction could not be the cause of rho - pi puzzle.