The Fast Track Trigger at the H1 experiment design concepts and algorithms

The HI Collaboration has built a new Fast Track Trigger which performs a full reconstruction of charged particles in a high multiplicity environment. At the first trigger level (2.3 mu s) coarse tracks are reconstructed in two dimensions whereas at the second level (23 mu s) all tracks are reconstructed with high precision in all three dimensions. This allows to identify particle resonances at the third trigger level (<= 100 mu s). The conceptual design and the implementation of the fast track finding algorithms are discussed. First results from the 2005 running period are presented. (c) 2006 Elsevier B.V. All rights reserved.