Measurement of the e+e- --> p anti-p cross section in the energy range from 3.0 to 6.5 GeV

TL;DR

This study measures the proton-antiproton production cross section and magnetic form factor in e+e- collisions between 3.0 and 6.5 GeV, providing new data at higher energies using initial-state radiation.

Contribution

First measurement of the proton magnetic form factor above 4.5 GeV energy range using initial-state radiation technique.

Findings

Proton-antiproton cross section measured across 3.0-6.5 GeV.

Proton magnetic form factor obtained at energies >4.5 GeV.

Branching fractions for J/psi and psi(2S) decays to p anti-p measured.

Abstract

The e+ e- --> p anti-p 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/psi --> p anti-p and psi(2S) --> p anti-p have also been measured.