Relatore
Dr.
Giuseppe Mandaglio
(University of Messina)
Descrizione
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 published this year.
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.
Autore principale
Dr.
Giuseppe Mandaglio
(University of Messina)
