Measuring the Hadronic Cross Section at KLOE using the Radiative Return

TL;DR

This paper reports on measuring the e+e- to pi+pi- cross section at the phi resonance using radiative return at KLOE, providing data crucial for understanding hadronic contributions to fundamental quantities.

Contribution

It introduces a method to extract the pi+pi- cross section from radiative events at the phi resonance, extending measurements to lower energies.

Findings

Preliminary invariant mass spectrum results obtained.

Cross section measurements consistent with previous data.

Method demonstrates effective use of radiative return at DAPHNE.

Abstract

We present a study of the reaction e+e- \to pi+pi-gamma at the phi peak with the KLOE detector at the phi-factory DAPHNE. This reaction allows us to obtain the cross section for \e+e- \to pi+pi- from the e+e- center-of-mass energy W = m_\phi = 1019 MeV down to threshold, i.e. 2m_pi < M_(pipi) < m_phi. This is called radiative return. The status of the analysis and preliminary results on the invariant mass spectrum of the two-pion-state are presented.