No indication of f0(1370) in pi pi phase shift analyses

TL;DR

This study reanalyzes pi pi phase shift data to investigate the existence of the f_0(1370) meson, finding no clear evidence for it in the analyzed reactions despite previous indications.

Contribution

The paper provides a comprehensive reanalysis of pi pi phase shifts, challenging the claimed presence of the f_0(1370) resonance in experimental data.

Findings

No clear signal of f_0(1370) in pi pi phase shifts

Resonance signals for f_0(1500) are observed

Background from f_0(600) complicates analysis

Abstract

The scalar meson f_0(1370) - indicated in particular in the low energy p\bar p \to 3 body reactions - is a crucial element in certain schemes of the scalar meson spectroscopy including glueballs. The most definitive results can be obtained from elastic and inelastic pi pi phase shift analyses using the constraints from unitarity where the discrete ambiguities can be identified and resolved. We reconsider the phase shift analyses for pi^+ pi^- \to pi+ \pi-, pi^0 pi^0, K \bar K, eta eta. While a clear resonance signal for f_0(1500) in the resp. Argand diagrams is seen in all channels above a large ``background'' from f_0(600) there is no clear signal of a second resonance ``f_0(1370)'' in this mass range in any reaction, at the level of \sim 10% branching ratio into pi-pi.