Status of the electromagnetic calorimeter trigger system at Belle II.

Abstract

The Belle II experiment at SuperKEKB collider in Japan has been under the construction toward physics run in 2017 with 40 times higher instantaneous luminosity than the KEKB collider. The main physics goal of the Belle II is to search for the New Physics in rare B decays and τ lepton decays. We have developed an Electromagnetic Calorimeter hardware trigger system that generates a trigger signal by two main triggers, total energy and cluster counting. Analog signals from 16 CsI(Tl) crystals are merged at ShaperDSP, and which are sent to FAM consisting of Flash-ADC and FPGA. ETM receives 52 FAM data from TMM and makes a ECL trigger signal which is sent to GRL and GDL, then the final Belle II trigger signal is generated by GDL which analyzes all trigger signals from each Belle II detector. In this article, the overall design scheme and current status of the ECL trigger system is reported.