CERN Accelerating science

LHCb Note
Report number	LHCb-PUB-2011-016 ; CERN-LHCb-PUB-2011-016 ; LHCb-INT-2011-030
Title	The HLT inclusive B triggers
Author(s)	Gligorov, Vladimir V (CERN) ; Thomas, Christopher (Rutherford ; U. Oxford (main)) ; Williams, Michael (Imperial Coll., London)
Note	LHCb-INT-2011-030
Submitted by	elodie.beaumont@cern.ch on 22 Sep 2011
Subject category	Particle Physics - Experiment
Note type	PHYS
Accelerator/Facility, Experiment	CERN LHC ; LHCb
Abstract	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%.
Copyright/License	Preprint: (License: CC-BY-4.0)

Corresponding record in: Inspire
Email contact(s) : Vladimir.Gligorov@cern.ch