Measurement of hadronic cross section at KLOE/KLOE-2

TL;DR

This paper reports on the measurement of the e+e- to pi+pi- cross section at KLOE/KLOE-2, which is crucial for determining the pion form factor and the muon g-2 contribution, combining multiple analyses for improved precision.

Contribution

It presents a combined analysis of several KLOE measurements to refine the e+e- to pi+pi- cross section and related quantities.

Findings

Preliminary combined results on the cross section.

Improved precision in the pion form factor measurement.

Updated contribution to muon g-2 calculations.

Abstract

The measurement of the $\sigma(e^+e^-\rightarrow \pi^+\pi^-)$ cross section allows to determine the pion form factor $| F_\pi |^2$ and the two pion contribution to the muon anomaly $a_\mu$. Such a measurement has been performed with the KLOE detector at $DA\Phi NE$, the Frascati $\phi$-factory.The preliminary results on the combination of the last analysis (KLOE12) with two previous published (KLOE08, KLOE10) will be presented in the following.