$f_0(500)$, $f_0(980)$ and $a_0(980)$ production in the $\chi_{c1} \to \eta \pi^+\pi^-$ reaction

TL;DR

This paper investigates the production of scalar mesons $f_0(500)$, $f_0(980)$, and $a_0(980)$ in the decay $oldsymbol{ ext{chi}_{c1} o ext{eta} ext{pi}^+ ext{pi}^-}$ using the chiral unitary approach, finding strong signals consistent with experimental data.

Contribution

It demonstrates that these scalar mesons can be dynamically generated from meson-meson interactions, supporting their interpretation as molecular states.

Findings

Clear signals for $a_0(980)$ and $f_0(500)$ in invariant mass distributions.

A smaller but significant signal for $f_0(980)$ was observed.

Results agree well with experimental data.

Abstract

We study the $\chi_{c1} \to \eta \pi^+ \pi^-$ decay, paying attention to the production of $f_0(500)$, $f_0(980)$ and $a_0(980)$ from the final state interaction of pairs of mesons that can lead to these three mesons in the final state, which is implemented using the chiral unitary approach. Very clean and strong signals are obtained for the $a_0(980)$ excitation in the $\eta \pi$ invariant mass distribution and for the $f_0(500)$ in the $\pi^+ \pi^-$ mass distribution. A smaller, but also clear signal for the $f_0(980)$ excitation is obtained. The results are contrasted with experimental data and the agreement found is good, providing yet one more test in support of the picture where these resonances are dynamically generated from the meson-meson interaction.