The scalars $a_0(980)$ and $f_0(980)$ in the process $D_s^+ \to K^{+} K^{-} \pi^{+}$

TL;DR

This paper analyzes the decay process D_s^+ -> K^+ K^- pi^+ using chiral unitary approach, revealing the dominant role of the f_0(980) resonance and questioning the lineshape models used by experiments.

Contribution

It introduces a dynamical generation model for the f_0(980) in the decay process, providing a more accurate description of the K^+K^- invariant mass distribution.

Findings

f_0(980) is the dominant contribution near the K^+K^- threshold.

The lineshape models used by BESIII and BABAR are not optimal near the threshold.

The chiral unitary approach effectively describes the S-wave pseudoscalar interactions.

Abstract

In this work, we have investigated the process $D_s^+\to K^+ K^- \pi^+$, taking into account the contributions from the $S$-wave pseudoscalar-pseudoscalar interaction within the chiral unitary approach, and also the intermediate $\phi$ resonance. By analyzing the BESIII and {\it BABAR} measurements, we conclude that the $f_0(980)$ state, dynamically generated from the $S$-wave pseudoscalar-pseudoscalar interaction, gives the dominant contribution close to the $K^+K^-$ threshold in the $K^+K^-$ invariant mass distribution of the decay $D_s^+\to K^+ K^- \pi^+$ in $S$-wave. On the other hand, our results imply that the lineshape adopted by BESIII and {\it BABAR} for the resonances $a_0(980)$ and $f_0(980)$ is not advisable in the fit to the data close to the $K^+K^-$ threshold.