At the Large Hadron Collider, the identification of jets originating from b quarks is important for searches for new physics and for measurements of standard model processes. A variety of algorithms has been developed by CMS to select b-quark jets based on variables such as the impact parameters of charged-particle tracks, the properties of reconstructed decay vertices, and the presence or absence of a lepton, or combinations thereof. The performance of these algorithms has been measured using data from proton-proton collisions at the LHC and compared with expectations based on simulation. The data used in this study were recorded in 2011 at root s = 7TeV for a total integrated luminosity of 5.0 fb(-1). The efficiency for tagging b-quark jets has been measured in events from multijet and t-quark pair production. CMS has achieved a b-jet tagging efficiency of 85 for a light-parton misidentification probability of 10 in multijet events. For analyses requiring higher purity, a misidentification probability of only 1.5 has been achieved, for a 70 b-jet tagging efficiency.

Identification of b-quark jets with the CMS experiment

ABBRESCIA, Marcello;BARBONE, LUCIA;CALABRIA, CESARE;CHHIBRA, SIMRANJIT SINGH;DE PALMA, Mauro;LUSITO, LETIZIA;MARANGELLI, Bartolomeo;MY, Salvatore;NUZZO, Salvatore Vitale;PACIFICO, NICOLA;POMPILI, ALEXIS;SELVAGGI, Giovanna;SINGH, GURPREET;VENDITTI, ROSAMARIA;
2013

Abstract

At the Large Hadron Collider, the identification of jets originating from b quarks is important for searches for new physics and for measurements of standard model processes. A variety of algorithms has been developed by CMS to select b-quark jets based on variables such as the impact parameters of charged-particle tracks, the properties of reconstructed decay vertices, and the presence or absence of a lepton, or combinations thereof. The performance of these algorithms has been measured using data from proton-proton collisions at the LHC and compared with expectations based on simulation. The data used in this study were recorded in 2011 at root s = 7TeV for a total integrated luminosity of 5.0 fb(-1). The efficiency for tagging b-quark jets has been measured in events from multijet and t-quark pair production. CMS has achieved a b-jet tagging efficiency of 85 for a light-parton misidentification probability of 10 in multijet events. For analyses requiring higher purity, a misidentification probability of only 1.5 has been achieved, for a 70 b-jet tagging efficiency.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11586/144439
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