Pass 8: Transforming the Scientific Performance of the Fermi Large Area Telescope

The event selection developed for the Fermi Large Area Telescope before launch has been periodically updated to reflect the constantly improving knowledge of the detector and the environment in which it operates. Pass 7, released to the public in August 2011, represents the most recent major iteration of this incremental process. In parallel, the LAT team has undertaken a coherent long-term effort aimed at a comprehensive revision of the entire event-level analysis, based on experience gained in the prime phase of the mission. This includes virtually every aspect of the data reduction process, from simulation of the detector to event reconstruction and background rejection. The potential improvements include (but are not limited to) a significant reduction in cosmic-ray background contamination coupled with an increased effective area, a narrower point-spread function, a better understanding of the systematic uncertainties and an extension of the energy reach for the photon analysis below 100 MeV and above a few hundred GeV. We present an overview of Pass 8 work and prospects for the near future.