Description of the processes $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$ in the NJL model with value of the vector coupling constant $g_{\rho }=6$

Abstract

It is shown that the processes $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$ can be described in a unified approach in satisfactory agreement with experiment using the vector coupling constant $g_{\rho }=6$. In this case, in addition to quark loops, it is also necessary to take into account meson loops corresponding to the next order in $1/N_c$. These loops must be taken into account when describing the $\gamma (W)\to \rho$ transition, as well as in interaction of mesons in the final state.

Comments: 10 pages, 9 figures