1664335 20150211084113.0 oai:cds.cern.ch:1664335 cerncds:FULLTEXT cerncds:atlas-conf Inspire 1282511 ATLAS-CONF-2014-004 eng ATLAS-COM-CONF-2014-003 The ATLAS collaboration Calibration of $b$-tagging using dileptonic top pair events in a combinatorial likelihood approach with the ATLAS experiment 2014 CERN Geneva 25 Feb 2014 20 p This note presents a new method to derive the $b$-jet tagging efficiency from data using a combinatorial likelihood approach applied to dileptonic $t\bar{t}$ events. Calibration results are obtained for the $pp$ collision data collected by the ATLAS experiment at the Large Hadron Collider at $\sqrt{s} = 8$ TeV, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. The $b$-jet tagging efficiency measurements are provided in the form of jet transverse momentum dependent scale factors which correct the $b$-tagging performance in simulation to that observed in data. The scale factors have been measured in the range 20-300 GeV and have a total uncertainty $\sim 2\%$ for jets with transverse momenta around 100 GeV. This represents a significant improvement in precision compared to alternative calibration methods. CONF CERN CDS-Invenio WebSubmit Detectors and Experimental Techniques SzGeCERN Conference talks on ATLAS SzGeCERN CERN Flavour tagging calibration CERN TOP CERN BTAGGING CERN INTNOTE INTNOTEATLASPUBL CERN LHC ATLAS PH-EP http://cds.cern.ch/record/1644784 Original Communication (restricted to ATLAS) http://cds.cern.ch/record/1664335/files/ATLAS-CONF-2014-004.pdf Stamped by WebSubmit: 25/02/2014 martin.erik.gerd.zur.nedden@cern.ch F.Filthaut@science.ru.nl tim.scanlon@cern.ch n 201470 91 PUBLIC 000737065CER INTNOTEATLASPUBL NOTE