Optimization of the LHCb track reconstruction

21st International Conference on Computing in High Energy and Nuclear Physics

物理学;计算机科学

Storaci, Barbara^1

University of Zurich, Physik-Institut, Winterthurerstrasse 190, Zurich, Switzerland^1

关键词: Complementary sets;    Different stages;    High-efficiency;    High-level triggers;    Pattern recognition algorithms;    SIMD instructions;    Track reconstruction;    Tracking station;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/664/7/072047/pdf
DOI  :  10.1088/1742-6596/664/7/072047

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

The LHCb track reconstruction uses sophisticated pattern recognition algorithms to reconstruct trajectories of charged particles. Their main feature is the use of a Hough- transform like approach to connect track segments from different sub-detectors, allowing for having no tracking stations in the magnet of LHCb. While yielding a high efficiency, the track reconstruction is a major contributor to the overall timing budget of the software trigger of LHCb, and will continue to be so in the light of the higher track multiplicity expected from Run II of the LHC. In view of this fact, key parts of the pattern recognition have been revised and redesigned. In this document the main features which were studied are presented. A staged approach strategy for the track reconstruction in the software trigger was investigated: it allows unifying complementary sets of tracks coming from the different stages of the high level trigger, resulting in a more flexible trigger strategy and a better overlap between online and offline reconstructed tracks. Furthermore the use of parallelism was investigated, using SIMD instructions for time-critical parts of the software.