Track reconstruction in the MUCH and TRD detectors of CBM

In this contribution we present new developments and results for the LIT track reconstruction package for CBM in the CbmRoot framework. The reconstruction package is organized to be flexible with respect to feasibility studies of different physics channels and to optimization of the detector geometries. The tracking software has been redesigned to make it more general and to simplify the support. The main components of the reconstruction package include track finding, fitting, propagation and selection. The track propagation algorithm has been improved considerably. The algorithm consists of track extrapolation, calculation of material effects and the geometry navigator, managed by the track propagator, which performs the transport of the track. The extrapolation part relates to the geometrical extrapolation, governed by the equations of motion. In case of the absence of a magnetic field a straight line model is used for the tracks. In the presence of a magnetic field the equation of motion for a charged particle is solved with the 4th order Runge-Kutta method with a parallel integration of the derivatives. Material effects are taken into account by updating the track parameters and covariance matrix due to energy loss (ionization, bremsstrahlung and direct pair production) and multiple Coulomb scattering (Highland formula). The implementation of the geometry navigator is based on the ROOT geometry package which allows track propagation independent on the geometry. The track propagation algorithm is done in steps to allow for more precise calculation for material effects. The GEANE algorithm is also included in the track reconstruction as an alternative to the LIT propagation algorithm. A detailed description of the developed track propagation algorithm and its comparison with GEANE is given in Ref. [1]. The track finding algorithm was divided in two parts, track recognition and track selection. The track recognition is based on the track following method with branches and Kalman Filter. Reconstructed tracks are selected for their quality afterwards. The track selection is based on track quality criteria and checks for shared hits between tracks. The detailed layout of the detectors is still under discussion. For the TRD and the MUCH stations in the high track density region pad layout is forseen based on MWPC or GEM chamber technology. For the later detector stations in MUCH where track densities are low, straw tube chambers are under discussion.As this detectors provide not pad size but long strip like hits, the tracking algorithm was modified in order to support all these structures. The track reconstruction algorithm has been tested for