# The production of the $f_1(1285) \gamma$ and $a_1(1260) \gamma$ in colliding $e^{+}e^{-}$-beams in threshold domain

## TL;DR

This paper investigates the production of $f_1(1285)\,\gamma$ and $a_1(1260)\,\gamma$ in electron-positron collisions near threshold using an extended Nambu--Jona-Lasinio model, analyzing intermediate meson contributions and decay widths.

## Contribution

It introduces a detailed analysis of meson channel contributions in $e^{+}e^{-}$ collisions producing $f_1(1285)$ and $a_1(1260)$ within the extended NJL model, including decay width calculations.

## Key findings

- $
ho$-meson channels dominate in $f_1(1285)\,\gamma$ production.
- $
ho$ and $\\omega$ channels contribute equally in $a_1(1260)\,\gamma$ production.
- Calculated decay widths for various meson transitions.

## Abstract

The processes $e^{+}e^{-}\!\to\! (f_1(1285), a_1(1260))\gamma$ in threshold domain are considered in the framework of the extended Nambu--Jona-Lasinio model. The channels with the ground $\rho(770)$, $\omega(782)$ and radially excited $\rho(1450)$, $\omega(1420)$ intermediate meson states are taken into account. It is shown that in the process $e^{+}e^{-}\to f_1(1285)\gamma$, the probability of the subprocesses with $\rho$-mesons significantly exceeds the probability of the subprocesses with $\omega$-mesons, whereas, in the process $e^{+}e^{-} \to a_1(1260) \gamma$, $\rho$- and $\omega$-channels give approximately equal contributions. The mechanism of this effect is discussed. The radiative decay widths of $\rho(1450)\!\to\! f_{1}(1285)\gamma$, $\omega(1420)\!\to\! f_{1}(1285)\gamma$, $\rho(1450)\!\to\! a_1(1260)\gamma$ and $\omega(1420)\!\to\! a_1(1260)\gamma$ are calculated.