The phi(1020) a0(980) S-wave scattering and hints for a new vector-isovector resonance

TL;DR

This study models phi(1020)a0(980) S-wave scattering using chiral Lagrangians, revealing a possible new vector-isovector resonance near 2.03 GeV and explaining experimental cross section features.

Contribution

It introduces a parameter-free approach to dynamically generate the isovector resonance and links it to experimental e+ e- scattering data.

Findings

Identification of a potential new resonance around 2.03 GeV.

Large final state re-scattering effects significantly alter cross sections.

Reproduction of the e+ e- -> phi(1020) f0(980) cross section.

Abstract

We have studied the phi(1020)a0(980) S-wave scattering at threshold energies employing chiral Lagrangians coupled to vector mesons by minimal coupling. The interaction is described without new free parameters by considering the scalar isovector a0(980) resonance as dynamically generated in coupled channels, and demanding that the recently measured e+ e- -> phi(1020) f0(980) cross section is reproduced. For some realistic choices of the parameters, the presence of a dynamically generated isovector companion of the Y(2175) is revealed. We have also investigated the corrections to the e+ e- -> phi(1020) pi0 eta reaction cross section that arise from phi(1020)a0(980) re-scattering in the final state. They are typically large and modify substantially the cross section. For a suitable choice of parameters, the presence of the resonance would manifest itself as a clear peak at sqrt{s}~2.03 GeV in e+ e- -> phi(1020) pi0 eta.