The HLT inclusive B triggers

The inclusive HLT strategy relies on triggering any B decay based on two signatures: a single significantly displaced, high transverse momentum track, and a significantly displaced vertex containing this track and 1-3 other tracks, with high total transverse momentum. In order to provide optimal signal efficiency and background rejection the displaced vertex selection is implemented in a novel boosted decision tree algorithm incorporating information about the experimental resolution in the boosting procedure to protect against overtraining. The performance of these triggers has been commissioned using data taken during 2011 LHCb running and is evaluated here in a data-driven manner. The HLT inclusive triggers are found to have a rejection factor of around 1000 with respect to events selected by the L0 hardware trigger and a bbar purity close to 100%.