The HERA-B SLT Group's Homepage
The Second Level Trigger (SLT) is a Region-of-Interest (RoI) based algorithm, running on a farm of 240 Pentium II/III PC's under the Hera-B data acquisition system.
It has been designed to trigger on signatures of charged lepton or hadron pairs, seeded by the First Level Trigger (FLT) output candidates. The main SLT functionalities are:
- Refine the track candidates from the FLT using all tracking stations downstream of the Hera-B Magnet
- Transport the track candidates through the Magnet into the Silicon Vertex Detector
- Apply a dilepton vertex cut (J/Psi) and eventually a detached vertex cut to the track pair candidates
The system was designed to handle 50KHz input rate, for a background reduction factor of about 100. The design efficiency on J/psi is at the ~90% level.
19-Jan-01 by T.Núñez
27-Feb-01 by P.Kreuzer
29-Mar-01 by L.Sözüer