BaBar Level 1 Drift Chamber Trigger Upgrade

TL;DR

The BaBar experiment upgrades its Level 1 Drift Chamber Trigger with new Z-Pt-Discriminator boards to significantly reduce background triggers while maintaining high physics efficiency at increased luminosity.

Contribution

Introduction of Z-Pt-Discriminator VME boards utilizing stereo hit info to improve background rejection in the trigger system.

Findings

Background trigger rate reduced by over 50%

Achieved z-coordinate resolution of a few centimeters

Maintained high trigger efficiency for physics events

Abstract

As PEP-II is exceeding the original design luminosity, BaBar is currently upgrading its Level 1 Drift Chamber Trigger (DCT) to reduce the rate of background Level 1 triggers by more than 50% while preserving the high Level 1 trigger physics efficiency. New Z-Pt-Discriminator VME boards (ZPD) utilizing the stereo hit information from the drift chamber are being built to extract the track z coordinate at the beam line with a resolution of a few centimeters.