Measuring the phase between strong and EM J/Psi decay amplitudes

TL;DR

This paper proposes a method to measure the phase difference between strong and electromagnetic decay amplitudes of J/Psi using interference patterns observed in an energy scan below the resonance, enabling a model-independent analysis.

Contribution

It introduces a novel approach to determine the relative phase of decay amplitudes in J/Psi decays through a c.m. energy scan, which has not been done before in a model-independent manner.

Findings

Potential to measure the phase difference in all exclusive final states.

Provides a new experimental technique at BESIII.

Enables model-independent access to decay amplitude phases.

Abstract

A c.m. energy scan below the J/Psi peak foreseen in the next future at BESIII can probe the existence in all the exclusive possible final states of an interference pattern between the resonant e+e- => J/Psi => hadrons and non-resonant e+e+ => hadrons amplitudes. The relative phase of the strong J/Psi decay amplitude with respect to the electromagnetic one can hence be accessed for the first time in a model independent way.