A practical guide to unravel time-like transition form factors

Abstract

A method to determine masses, widths and coupling constants of vector mesons, like $\phi$(1020) , $\omega$(782) and $\rho^{0}_{}$(770) recurrences is defined. Starting from data on decay rates and cross-sections for the processes: $\phi$ → M _I $\gamma$ , $\phi$ → M _I e ⁺ e ^- and e ⁺ e ^- → M _I $\phi$ , where M_I is a pseudoscalar or scalar meson with isospin I = 0, 1 , the time-like transition form factors, which describe the vertex $\phi$ $\gamma$ M _I , are parameterized using a vector-meson-propagators description in the low-energy region ( < 3-4 GeV), the quark-counting rule prescription for the high-energy behavior, and the analyticity imposed by means of the dispersion relations.