Does $J/\psi \to {\pi }^{+}{\pi }^{-}$ fix the Electromagnetic Form Factor $F_{\pi }(t)$ at $t=M_{J/\psi }^2$?

Abstract

We show that the $J/\psi \to {\pi }^{+}{\pi }^{-}$ decay is a reliable source of information for the electromagnetic form factor of the pion at $t=M_{J/\psi }^2=9.6{\mathrm{GeV}}^2$ by using general arguments to estimate, or rather, put upper bounds on, the background processes that could spoil this extraction. We briefly comment on the significance of the resulting $F_{\pi }(M_{J/\psi }^2)$.

Comments: 10 pages revtex manuscript, one figure--not included, U. of MD PP #94-001