Rapid 3-D track reconstruction with the BABAR trigger upgrade

A new hardware trigger system based on tracks detected by a stereo drift chamber has been developed for the BABAR experiment at the Stanford Linear Accelerator Center. The z/sub 0/p/sub T/ Discriminator (ZPD) is capable of fast, three-dimensional reconstruction of charged particle tracks and provides rejection of background events due to beam particles interacting with the beam pipe at the first-level trigger. Over 1 gigabyte of data is processed per second by each ZPD module. Rapid track reconstruction has been realized using Xilinx Virtex-II FPGAs.