A fast track reconstruction algorithm for the ATLAS second level trigger is
presented. The timing performance (3.5 ms for a jet reconstruction at low
luminosity) is satisfactory; the transverse impact parameter resolution (75
mum) is sufficient to perform an on-line b-tagging, and the full three-dim
ensional reconstruction produces good seeds for more sophisticated track se
arches. (C) 2001 Elsevier Science B.V. All rights reserved.