The Concurrent Track Evolution algorithm: extension for track finding in the inhomogeneous magnetic field of the HERA-B spectrometer

The Concurrent Track Evolution method, which was introduced in a previous paper (Mankel, Nucl. Instr. and Meth. A 395 (1997) 169), has been further explored by applying it to the propagation of track candidates into an inhomogeneous magnetic field volume equipped with tracking detectors, as is typical for forward B spectrometers like HERA-B or LHCb. Compared to the field-free case, the method was extended to three-dimensional propagation, with special measures necessary to achieve fast transport in the presence of a highly variable magnetic field. The performance of the method is tested on HERA-B Monte Carlo events with full detector simulation and a realistic spectrometer geometry.