The pion form factor at timelike momentum transfers in a dispersion approach

D. Melikhov, O. Nachtmann, T. Paulus

We consider a model with $\rho \pi \pi$, $\rho KK$, and gauge-invariant $\rho \gamma$ couplings and obtain the pion form factor $F_{\pi }$ at timelike momentum transfers by resummation of pion and kaon loops…