The Lhc trigger system

The Lhc experiment intends to perform highly accurate measurements on C P-violating processes and rare decays of B-mesons at the Large Hadron Collider. The ratio between the expected p-p inelastic cross-section (about 100 mb) and the b-b cross-section (0.5 mb) demands for a very robust and efficient trigger system. In this paper the two trigger levels (Level-0 and High Level Trigger) foreseen for the experiment are described and their main performance analyzed. The expected annual yields of some of the most interesting B-decay channels are also summarized.