Leonard Koch
Sören Lange,
Wolfgang Kühn
Study of improved K_S^0 detection for the Belle II Detector
2015
2015
In this work, an online tracking algorithm is developed and evaluated focusing on the reconstruction of charged pions from displaced vertices, the characteristic decay topology of K_s^0 mesons. All six VXD layers are used. The algorithm, which may be used on the FPGA-based PXD DAQ system, is based on the fast Hough transform applied to the hits mapped onto the conformal plane. The amount of background is reduced by a two stage neural network filtering system. Applied to data from a simulation of 10 000 typical Belle II events, the algorithm is adjusted to a fake rate of 90% being considered as tolerable, resulting in a pion reconstruction efficiency of 81.4 %. An alternative setup has a fake rate of 50 % and an efficiency of 63.6 %. The gained K_S^0 reconstruction efficiencies by the additional employment of the algorithm developed in this work are 5.0 % and 1.4 %, respectively, compared to the performance of the existing track finders.