Track reconstruction in all Brahms versions since 2.00 is performed by a complex software package, the largest part of which has been adapted from corresponding software in actual use at the LEP experiments. Code from ALEPH, DELPHI and OPAL was merged with dedicated new code to achieve the desired functionality. This implies, however, that the Brahms track reconstruction package is a collection of completely different programming styles, making it sometimes hard to understand the structure and basic ideas of the code. This document intends to support further Brahms track reconstruction development, tuning and debugging by giving a walk-through through all relevant components of the track reconstruction software. Important parameters are discussed as well as known shortcomings of the code (as of Brahms 3.05).
First, a brief overview over the modules of the reconstruction code will be given. The main part of this document will then describe the track reconstruction process routine by routine. This document will conclude with a set of receipts for tuning the performance of Brahms and adding or changing subdetectors.
This note is based on Brahms version 3.05 as of November 1, 2002. However, most statements should be valid for a large variety of Brahms versions since 2.00.