We have measured the cross section Ï (e+e-â Ï+Ï-Î³ (Î³)) at DAÎ¦NE, the Frascati Ïsymbol-factory, using events with initial state radiation photons emitted at small angle and inclusive of final state radiation. We present the analysis of a new data set corresponding to an integrated luminosity of 240 pb-1. We have achieved a reduced systematic uncertainty with respect to previously published KLOE results. From the cross section we obtain the pion form factor and the contribution to the muon magnetic anomaly from two-pion states in the mass range 0.592 < MÏ Ï< 0.975 GeV. For the latter we find ÎÏ ÏaÎ¼= (387.2 Â± 0.5statÂ± 2.4expÂ± 2.3th) Ã 10-10. Â© 2008 Elsevier B.V. All rights reserved.
|Titolo:||Measurement of Ï (e+e-â Ï+Ï-Î³ (Î³)) and the dipion contribution to the muon anomaly with the KLOE detector|
|Data di pubblicazione:||2009|
|Appare nelle tipologie:||1.1 Articolo in rivista|