Speaker
Description
To efficiently separate hadrons in the forward end-cap of the Belle II spectrometer, an aerogel proximity focusing Ring Imaging Detector is installed in the high magnetic field between the central drift chamber and electromagnetic calorimeter. Cherenkov photons, emitted in the double layer aerogel radiator are expanded in the 16 cm empty space and detected on the photon detector comprising by 420 Hybrid avalanche photo diodes. Photons at the outer edge of the detector, which would not be detected, are reflected back towards the photo sensors. The readout electronics working in a threshold mode will record hit patterns created during beam collisions. A particle identification algorithm based on the two dimensional extended maximum likelihood technique will be used to assign probabilities for different particle hypotheses of tracks traversing the aerogel RICH detector. The likelihood function combines the probabilities for different photon emission and path hypotheses
To tune and to determine detector performance, we will use particles, unambiguously identified by other subsystems or only by tracking system.
In the presentation, the particle identification algorithm will be presented together with the expected simulated performance. We will present the strategy to determine a kaon identification efficiency by using $D^{\pm ∗}$ decays. Data from first beam collisions will also be shown.
