Hamburg 2016 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 84: Trigger und DAQ III

T 84.9: Vortrag

Mittwoch, 2. März 2016, 18:45–19:00, VMP11 HS

Study of improved K_S⁰ detection at the Belle II detector — •Leonard Koch, Wolfgang Kühn, and Sören Lange for the Belle II collaboration — II. Physikalisches Institut, JLU Gießen

In the near future, the Belle II experiment at the SuperKEKB accelerator at KEK in Tsukuba, Japan, will start operation at a luminosity a factor 40 higher than its predecessor experiment, Belle. The physics program includes the search for physics beyond the Standard Model of particle physics by the investigation of CP violating processes and rare B meson decays. Many important decay channels involve K_S⁰ mesons.

The detector features two layers of silicon pixel cells (PXD) closest to the interaction point surrounded by four layers of double sided silicon strip detectors (SVD). The high backgoround level of the Pixel Detector requires an online data reduction system: Using the SVD and the surrounding detectors, the online reconstructed tracks of charged particles are extrapolated to the PXD layers, where Regions of Interest (ROIs) are defined around the intercepts. Only the pixel data inside these ROIs are stored. Thus, particles creating an insufficient number of hits in the outer detectors are not reconstructed and subsequently no ROIs are created, resulting in the loss of the related hits in the Pixel Detector. As a consequence, particles creating a sufficient number of hits in all six layers, but not in the outer four, are lost.

In this contribution, we perform online tracking using all six layers to find the tracks of pions for improved K_S⁰ detection. The combinatorics of the hit-track assignments is reduced by artificial neural networks.

This work is supported by the BMBF under grant 05H1SRGKBA.