Results and Plans of the PEP-II B-Factory

PEP-II is an e + e - B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). PEP-II has delivered, over the past five years, an integrated luminosity to the BaBar detector of about 240 fb -1 and has reached a luminosity of 9.21x10 33 /cm 2 /s. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of at least 2.4x10 34 /cm 2 /s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower betay* interaction region operation, and coupling control. A view of the PEP-II tunnel is shown in Figure 1. The present parameters of the PEP-II B-Factory are shown in Table 1 compared to the design. The present peak luminosity is over three times the design and the best integrated luminosity per month is 16 fb -1 that is five times the design. The highest luminosity per month is shown in Figure 2. The integrated luminosity over a month is shown in Figure 3 and the total integrated luminosity in Run 4 in shown in Figure 4. The progress in integrated luminosity has come from correcting the orbits, lowering beta y*, moving the fractional horizontal tunes in both rings to just above the half integer (<0.52), and trickle injection of both beams.