CERN Accelerating science

Internal Note and Article
Report number	LHCb-PROC-2012-018 ; CERN-LHCb-PROC-2012-018
Title	Performance and Upgrade Plans of the LHCb Trigger System
Author(s)	Gligorov, Vladimir V (CERN)
Collaboration	on behalf of the LHCb Collaboration
Publication	2013
Imprint	14 Jun 2012
Number of pages	4
In:	Nucl. Instrum. Methods Phys. Res., A 718 (2013) 26-29
In:	12th Pisa Meeting on Advanced Detectors: Frontier Detector for Frontier Physics, La Biodola, Isola d'Elba, Italy, 20 - 26 May 2012, pp.26-29
DOI	10.1016/j.nima.2012.08.076
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; LHCb
Free keywords	detector ; trigger ; upgrade ; flavour physics
Abstract	The trigger of the LHCb experiment consists of two stages : an initial hardware trigger, and a high-level trigger implemented in a farm of parallel-processing CPUs. It reduces the event rate from an input of 15 MHz to an output rate of around 4 kHz. In order to maximize efficiencies and minimize biases, the trigger is designed around inclusive selection algorithms, culminating in a novel boosted decision tree which enables the efficient selection of beauty hadron decays based on a robust partial reconstruction of their decay products. In order to improve performance, the LHCb upgrade aims to significantly increase the rate at which the detector will be read out, and hence shift more of the workload onto the high-level trigger. It is demonstrated that the current high-level trigger architecture will be able to meet this challenge, and the expected efficiencies in several key channels are discussed in context of the LHCb upgrade.
Related document	Slides LHCb-TALK-2012-165
Copyright/License	Preprint: (License: CC-BY-4.0)

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