The PEP-II e+e-collider has been operating for two years with the BaBar detector at the energy of the Upsilon 4S resonance. The peak luminosity has reached 3.3 ×1033/cm2/s with 693 bunches with a positron current of 1.5 A and an electron current of 0.8 A. PEP-II has delivered in excess of 38 fb-1 of data to BaBar. The beam-beam tune shift limits are approaching 0.05-0.07 horizontally and 0.03-0.05 vertically. The electron cloud instability ECI enlarges the positron beam size at high currents but is reduced by a solenoidal field on the vacuum chambers. The beam currents in PEP-II are being raised to increase the number of bunches and the luminosity. Over the next few years the luminosity goal for PEP-II is 1034/cm2/s.

We report the results of a search for the bottomonium ground state etab(1S) in the photon energy spectrum with a sample of (109+/-1) million of Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at Egamma=921.2(-2.8)+2.1(stat)+/-2.4(syst) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Upsilon(3S)-->gammaetab(1S). This photon energy corresponds to an etab(1S) mass of 9388.9(-2.3)+3.1(stat)+/-2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-etab(1S) mass splitting is 71.4(-3.1)+2.3(stat)+/-2.7(syst) MeV/c2. The branching fraction for this radiative Upsilon(3S) decay is estimated to be [4.8+/-0.5(stat)+/-1.2(syst)]x10(-4).

We report e;{+}e;{-}-->bb[over ] cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the SLAC PEP-II e;{+}e;{-} collider. A total relative error of about 5% is reached in more than 300 center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Upsilon(10860) and Upsilon(11020) resonances. In particular we show that their widths may be smaller than previously measured.

The BaBar detector operated successfully at the PEP-II asymmetric e +e- collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking. © 2013 Elsevier B.V.