Measurement of the e+e-→pp̄ cross section in the energy range from 3.0 to 6.5 GeV

Abstract

The e+e-→pp̄ cross section and the proton magnetic form factor have been measured in the center-of-mass energy range from 3.0 to 6.5 GeV using the initial-state radiation technique with an undetected photon. This is the first measurement of the form factor at energies higher than 4.5 GeV. The analysis is based on 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider at e+e - center-of-mass energies near 10.6 GeV. The branching fractions for the decays J/ψ→pp̄ and ψ(2S)→pp̄ have also been measured. © 2013 American Physical Society.