Clark, Brian LeeFranklin, MelissaHuth, JohnIppolito, ValerioLazovich, TomoLopez Mateos, DavidMercurio, KevinMorii, MasahiroSpearman, WilliamSun, SiyuanTolley, EmmaTuna, AlexanderYen, AndyZambito, Stefano2017-11-302016ATLAS Collaboration. 2016. “Measurements of Fiducial Cross-Sections for tt¯ Production With One or Two Additional b -Jets in pp Collisions at √s = 8 TeV Using the ATLAS Detector.” The European Physical Journal C 76 (1) (January). doi:10.1140/epjc/s10052-015-3852-4. http://dx.doi.org/10.1140/epjc/s10052-015-3852-4.1434-6044http://nrs.harvard.edu/urn-3:HUL.InstRepos:34401539Fiducial cross-sections for tt¯ production with one or two additional b -jets are reported, using an integrated luminosity of 20.3 fb -1 of proton–proton collisions at a centre-of-mass energy of 8 TeV at the Large Hadron Collider, collected with the ATLAS detector. The cross-section times branching ratio for tt¯ events with at least one additional b -jet is measured to be 950 ± 70 (stat.) -190+240 (syst.) fb in the lepton-plus-jets channel and 50 ± 10 (stat.) -10+15 (syst.) fb in the eμ channel. The cross-section times branching ratio for events with at least two additional b -jets is measured to be 19.3 ± 3.5 (stat.) ± 5.7 (syst.) fb in the dilepton channel ( eμ , μμ , and ee ) using a method based on tight selection criteria, and 13.5 ± 3.3 (stat.) ± 3.6 (syst.) fb using a looser selection that allows the background normalisation to be extracted from data. The latter method also measures a value of 1.30 ± 0.33 (stat.) ± 0.28 (syst.)% for the ratio of tt¯ production with two additional b -jets to tt¯ production with any two additional jets. All measurements are in good agreement with recent theory predictions.en-USJournal Article2017-11-3010.1140/epjc/s10052-015-3852-4