Measurement of properties of additional jets in top quark pair decays using $e\mu$ events with 2 $b$-jets in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

The transverse momentum and multiplicity of additional jets produced in association with top quark pairs are measured in 20.1 fb$^{-1}$ proton-proton collisions at $\sqrt{s}=8$ TeV collected in 2012 with the ATLAS experiment at the LHC. Jets are selected from $t\bar{t}$ events with an opposite-charge $e\mu$ pair and at least two $b$-tagged jets in the final state. The reconstructed jets are fully corrected for detector effects to obtain particle-level distributions in the fiducial region. The corrected data are compared to several Monte Carlo models.