Orateur
Dr
Graziano Venanzoni
(INFN - Laboratori Nazionali di Frascati)
Description
The KLOE experiment at the $\phi$ factory DA$\Phi$NE in Frascati
(near Rome) is the first to have employed Initial State Radiation (ISR)
to precisely determine the $e^+e^-\to\pi^+\pi^-(\gamma)$ cross section below 1 GeV. Such a measurement is particularly important to test the Standard Model calculation for the (g-2) of the muon, where a long standing 3$\sigma$ discrepancy is observed.
In 2005 and 2008 KLOE has published a measurement of the
$\pi^+\pi^-$ cross section with the photon emitted at small angle, and a new independent measurement with the photon emitted at large angle using data taken in 2006 at a collision energy of 1 GeV ({\it i.e.} 20 MeV below the $\phi$-peak) has been accepted for publication.
While these measurements were normalized to the DA$\Phi$NE luminosity
using large angle Bhabha scattering,
a new analysis has been performed which derives the
pion form factor directly from the $\pi^+\pi^-\gamma(\gamma)/\mu^+\mu^-\gamma(\gamma)$ ratio.
We present the KLOE results and discuss future prospects for these measurements as well as their impact on the evaluation of the hadronic contribution to the muon anomaly.
Auteur principal
Dr
Graziano Venanzoni
(INFN - Laboratori Nazionali di Frascati)
