String Banana Template Method for tracking in a high-multiplicity environment with significant multiple scattering

A String Banana Template Method (SBTM) for track reconstruction in the presence of significant Multiple Scattering (MS) is described. The main idea of the method is based on the features of ensembles of tracks selected by three-fold coincidences. The SBTM provides a narrower search window than other methods by exploiting the features of such ensembles: it deals with particular ''branches'' in the MS ''tree''. A two-step track model with additional parameters to account for MS is used. The SBTM uses stored template fields generated by precise Monte Carlo (MC) simulation. SBTM capabilities in terms of track parameter resolution are demonstrated for a model spectrometer. This method has been implemented in the ROOT C++ framework and tested with MC simulations as well as with data from a heavy ion collision experiment using a silicon-based spectrometer with a complex geometry, moderate segmentation (∼mm) and non-uniform magnetic field. Primary tracks in the most central Au-Au collisions at sNN=200GeV with occupancy >20% and momenta down to ∼80MeV/c (for pions) have been reconstructed with high efficiency