Measurement of sigma-(e(+)e(-) -> pi(+)pi(-)) from threshold to 0.85 GeV2 using initial state radiation with the KLOE detector
- Ambrosino, F
- Archilli, F
- Beltrame, P
- Bencivenni, G
- Bini, C
- Bloise, C
- Bocchetta, S
- Bossi, F
- Branchini, P
- Capon, G
- Capussela, T
- Ceradini, F
- Ciambrone, P
- De Lucia, E
- De Santis, A
- De Simone, P
- De Zorzi, G
- Denig, A
- Di Domenico, A
- DI DONATO, Camilla
- Di Micco, B
- Dreucci, M
- Felici, G
- Fiore, S
- Franzini, P
- Gatti, C
- Gauzzi, P
- Giovannella, S
- Graziani, E
- Jacewicz, M
- Kluge, W
- Lee Franzini, J
- Leone, D
- Massarotti, P
- Meola, S
- Miscetti, S
- Muller, S
- Murtasa, F
- Napolitano, M
- Nguyen, F
- Passeri, A
- Patera, V
- Santangelo, P
- Taccini, C
- Tortora, L
- Venanzoni, G
- Versaci, R.
DOIAbstract
We have measured the cross section of the radiative process e(+)e(-) -> pi(+)pi(-)gamma with the KLOE detector at the Frascati phi-factory DA(1)NE, from events taken at a CM energy W =1 GeV. Initial state radiation allows us to obtain the cross section for e(+)e(-) -> pi(+)pi(-), the pion form factor vertical bar F-pi vertical bar(2) and the dipion contribution to the muon magnetic moment anomaly, Delta alpha(pi pi)(mu) = (478.5 +/- 2.0(stat) +/- 5.0(syst) +/- 4.5(th)) x 10(-10) in the range 0.1 < M-pi pi(2) <0.85 GeV2, where the theoretical error includes a SU(3) chi PT estimate of the uncertainty on photon radiation from the final pions. The discrepancy between the Standard Model evaluation of alpha(mu) and the value measured by the Muon ...