Dortmund 2021 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 21: Data analysis, Information technology I
T 21.8: Vortrag
Montag, 15. März 2021, 17:45–18:00, Tu
Online Event Selection using GPUs for the Mu3e experiment — •Valentin Henkys for the Mu3e collaboration — Johannes Gutenberg University Mainz
The Mu3e experiment searches for physics beyond the Standard Model using the lepton flavour violating decay µ+ → e+ e− e+. Observing the decay products of 1 · 108 µ/s results in a data rate of 80Gbps. An online algorithm for graphics processing units (GPU) is presented, reducing the data rate with the Mu3e filter farm by a factor of over 100, to bring it below 100MBps. The filter farm consists of 12 PCs running this algorithm on one GPU each.
The algorithm is divided into three parts. The first step selects possible event candidates using simple and fast geometric selection criteria, reducing the candidates to under 2.5% of the initial set. These are then used in the second step, reconstructing the helical tracks of the electrons and positrons. Finally these tracks are used to reconstruct the event vertex. To fulfill the high performance requirements, fast geometric considerations are used instead of a full vertex fit.
The algorithm is able to reduce the data rate by a factor of over 100 while keeping 98% of the events found by the offline algorithm.