The Contribution of One-Photon Annihilation at psi(2S) in e+e- Experiment

TL;DR

This paper investigates the impact of one-photon annihilation processes at psi(2S) in e+e- experiments, emphasizing their importance in accurately measuring branching ratios of specific decay modes.

Contribution

It provides a phenomenological estimation of one-photon annihilation contributions at psi(2S), highlighting their significance in branching ratio determinations.

Findings

One-photon annihilation contributions significantly affect measured decay modes.

At least 10 pb of data below psi(2S) peak is required for accurate measurements.

Electromagnetic decay modes need correction for these contributions.

Abstract

The continuum one-photon annihilation at psi(2S) in e+e- experiment is studied. Such contributions to the measured final state omega pi0 and pi+pi- at psi(2S) mass are estimated by phenomenological models. It is found that these contributions must be taken into account in the determination of branching ratios of psi(2S) --> omega pi0 and psi(2S) --> pi+ pi-, as well as other electromagnetic decay modes. The study reaches the conclusion that in order for BES to obtain the correct branching ratios on these decay modes, at least 10 inverse pb of data below the psi(2S) peak is needed.