A probability-optimized fast timing trigger for the Belle II time of propagation detector

To search for physics beyond the Standard Model the Belle II experiment expects to operate at a trigger rate 30-50 times that of the Belle detector, which operated at KEKB, the world´s highest luminosity collider. To reduce backgrounds and semiconductor tracker occupancies, a nanosecond precision timing trigger is desired. Due to its intrisically fast timing, the time-of-propagation detector is an obvious choice for a prompt timing trigger signal, provided that the complex photon arrival pattern can be processed in real-time. This paper presents the analysis and preliminary implementation of a trigger that can be realized in programmable hardware and that determines single charged particle impact timing to a precision better than a few ns with a processing time of a couple microseconds.