The CDF L2 XFT Trigger Upgrade

Abstract

We briefly present the eXtremely Fast Tracker stereo track upgrade for the CDF Level 2 trigger system. This upgrade enabled full 3D track reconstruction at Level 2 of the 3-Level CDF online triggering system. Using information provided by the stereo layers of the Central Outer Tracker, we can decrease the trigger rate due to fake tracks by requiring the tracks to be consistent with a single vertex in all three dimensions but also by using the track information to "point" to the various detector components. We will also discuss the effectiveness of the Level 2 stereo track algorithm at achieving reduced trigger rates with high efficiencies during high luminosity running.