Cellular automaton and Kalman filter based track search in the HERA-B pattern tracker

The paper describes track reconstruction package OTR/ITR-CATS developed for the Pattern Tracker of the HERA-B experiment. This package employs a combined approach for track reconstruction based on the use of a cellular automaton for track searching and the Kalman filter techniques for track fitting. A similar reconstruction strategy is already successfully applied to the Vertex Detector System (VDS) (Nucl. Instr. and Meth. A 489 (2002) 389). However, hit efficiencies and resolutions of the Pattern Tracker lower than those of the VDS require much more delicate implementation of the method. The package developed has been tested on simulated data. The results of the tests regarding reconstruction efficiency, accuracy of estimates and computing time are presented