Scalar isovector resonance photoproduction through the final state meson-meson interactions

TL;DR

This paper models scalar isovector resonance photoproduction via meson-meson interactions, incorporating vector mesons and interchannel coupling, to predict cross sections and mass distributions related to scalar resonances like a0(980) and a0(1450).

Contribution

It introduces a comprehensive model including vector mesons in meson-meson loops, providing new insights into scalar resonance photoproduction and cross section predictions.

Findings

Predicted a0(980) cross sections align with other models.

Cross section for a0(1450) is significantly larger than quark model predictions.

Amplitudes with vector mesons are not suppressed in the on-shell approximation.

Abstract

We construct the amplitudes of $\pi\eta$ photoproduction taking into account the effects of the $\pi\eta$ - $K\bar K$ interchannel coupling. The idea of our model is close to the molecular description of scalar resonances with exception that apart from the pseudoscalar loops we include also vector mesons in the intermediate state loops. These amplitudes are used to calculate the $S$-wave cross sections and mass distributions in the $\pi\eta$ effective mass region corresponding to the scalar resonances $a_0(980)$ and $a_0(1450)$. The values we obtained for $a_0(980)$ are comparable with predictions of other models while the cross section for $a_0(1450)$ is about an order of magnitude larger than prediction based on the quark model. We show that the amplitudes with loops containing vector mesons calculated in the on-shell approximation are not suppressed in contrast to amplitudes containing only pseudoscalar loops. We estimate the cross sections for the $P$- and $D$- waves in the $\pi\eta$ channel.