VeloUT tracking for the LHCb Upgrade

This note describes track reconstruction in the LHCb tracking system upstream of the magnet, namely the VELO and UT sub-detectors. The implementation of the VeloUT algorithm and its performance in terms of track reconstruction efficiency, ghost rate and execution time per event are presented. The algorithm has been optimised for use in the Upgrade software trigger of LHCb. The momentum information obtained for the VeloUT tracks (due to a fringe magnetic field between the VELO and UT sub-detectors) can reduce the total execution time per event for the full tracking sequence. The performance of the tracking sequence with and without the use of VeloUT tracks is also presented.