Trigger Home Page

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The old Trigger home page, quite obsolete, can be accessed here.


The LHCb Trigger has three levels:

  • Level-0, a hardware level reducing the rate to 1 MHz in 4 μs
  • Level-1, a software level using selected data, reducing the rate to 40 kHz with about 1 ms processing time.
  • HLT, a software level running on the whole event, with an output rate up to 2 kHz and 10 ms processing time.

Three projects (or sub-projects) are working together to provide the LHCb trigger.

  • The L0 Project handles the hardware and software of the Level 0 trigger.
  • The Reconstruction (sub-project of the Computing project) handles the tracking and PID reconstruction both for Level-1 and HLT.
  • The Trigger Project handles the selection and monitoring algorithms, and optimize the working point of all triggers.

This page last edited by Olivier Callot on 28 February 2006.