pi^0 pi^0 Scattering Amplitudes and Phase Shifts Obtained by the pi^- P Charge Exchange Process

TL;DR

This paper analyzes pi^0 pi^0 scattering amplitudes from pi^- P charge exchange data at 9 GeV/c, revealing resonance signals and phase shifts, including the sigma resonance, using the Interfering Amplitude method.

Contribution

It provides new detailed measurements of pi^0 pi^0 scattering amplitudes and phase shifts, identifying key resonances and applying a refined analysis method.

Findings

Detection of f_0(1370) and f_2(1270) signals in scattering amplitudes

Observation of the sigma resonance with consistent Breit-Wigner parameters

Phase shifts analyzed successfully below Kbar K threshold

Abstract

The results of the analysis of the pi^0 pi^0 scattering amplitudes obtained with pi^- P charge exchange reaction, pi^- P --> pi^0 pi^0 n, data at 9 GeV/c are presented. The pi^0 pi^0 scattering amplitudes show clear f_0(1370) and f_2(1270) signals in the S and D waves, respectively. The pi^0 pi^0 scattering phase shifts have been obtained below Kbar K threshold and been analyzed by the Interfering Amplitude method with introduction of negative background phases. The results show a S wave resonance, sigma. Its Breit-Wigner parameters are in good agreement with those of our previous analysis on the pi^+ pi^- phase shift data.