Hamburg 2016 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 84: Trigger und DAQ III
T 84.8: Vortrag
Mittwoch, 2. März 2016, 18:30–18:45, VMP11 HS
Cosmic Ray Test of the Belle II z-Vertex Trigger — •Sara Neuhaus1, Sebastian Skambraks1, Yang Chen2, and Christian Kiesling2 — 1Technische Universität München — 2Max-Planck-Institut für Physik, München
The z-vertex trigger is part of the first level track trigger in the Belle II experiment. Its task is the rejection of tracks not coming from the interaction region, suppressing a large part of the machine background. Therefore the z-vertex trigger allows to relax other track trigger conditions and thus strongly increases the efficiency for channels with low track multiplicity (e.g. tau pair production). The track trigger works in several steps, first combining hits to track segments, followed by a 2D track finding in the transverse plane and finally the 3D reconstruction. Our method employs neural networks to estimate the z-vertex without explicit track reconstruction. For the first real test with cosmic rays special neural networks have been prepared. Although the track shape in the cosmic test is different than in the Belle II experiment, the neural networks require only a retraining with an appropriate data set to adapt to the new geometry.