Time-Integrated Luminosity Recorded by the BABAR Detector at the PEP-II e+e- Collider

Understand

We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the Upsilon(4S), Upsilon(3S) and Upsilon(2S) resonances and in a continuum region below each resonance.

• We measure the time-integrated luminosity by counting e+e- --> e+e- and (for the Upsilon(4S) only) e+e- --> mu+mu- candidate events, allowing additional photons in the final state.
• We use data-corrected simulation to determine the cross sections and reconstruction efficiencies for these processes, as well as the major backgrounds.
• Due to the large cross sections of e+e- --> e+e- and e+e- --> mu+mu-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties.