Measurement of the hadronic cross section at DAPHNE with the KLOE detector

TL;DR

This paper reports a precise measurement of the e+e- to pi+pi- cross section using initial state radiation at DAPHNE, providing data crucial for calculating the hadronic contribution to the muon g-2 anomaly.

Contribution

It introduces a novel measurement of the pi+pi- cross section at DAPHNE using initial state radiation, refining the data used for muon anomaly calculations.

Findings

Measured the pi+pi- cross section in the 0.37-0.93 GeV^2 range.

Extracted the pion form factor from the data.

Contributed to the calculation of the hadronic part of the muon g-2.

Abstract

We have measured the cross section sigma(e+e- \to pi+pi-gamma) as a function of the pi+pi- invariant mass, M_pipi, with the KLOE detector at DAPHNE (W=m_phi=1.02GeV). The photon in the above process is due to Initial State Radiation. Dividing by a theoretical radiator function we obtain the cross section sigma(e+e- \to pi+pi-) for the mass range 0.37<M_pipi^2<0.93GeV^2. We extract the pion form factor and the hadronic contribution to the muon anomaly, a_mu.