# Measurement of jet activity produced in top-quark events with an electron, a muon and two $b$-tagged jets in the final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

Abstract : Measurements of jet activity in top-quark pair events produced in proton--proton collisions are presented, using 3.2 fb$^{-1}$ of $pp$ collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Events are chosen by requiring an opposite-charge $e\mu$ pair and two $b$-tagged jets in the final state. The normalised differential cross-sections of top-quark pair production are presented as functions of additional-jet multiplicity and transverse momentum, $p_{\mathrm T}$. The fraction of signal events that do not contain additional jet activity in a given rapidity region, the gap fraction, is measured as a function of the $p_{\mathrm T}$ threshold for additional jets, and is also presented for different invariant mass regions of the $e\mu b\bar{b}$ system. All measurements are corrected for detector effects and presented as particle-level distributions compared to predictions with different theoretical approaches for QCD radiation. While the kinematics of the jets from top-quark decays are described well, the generators show differing levels of agreement with the measurements of observables that depend on the production of additional jets.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01390854
Contributor : Claudine Bombar <>
Submitted on : Wednesday, November 2, 2016 - 3:07:22 PM
Last modification on : Thursday, January 23, 2020 - 5:00:34 PM

### Citation

M. Aaboud, N. Berger, M. Delmastro, L. Di Ciaccio, S. Elles, et al.. Measurement of jet activity produced in top-quark events with an electron, a muon and two $b$-tagged jets in the final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2017, 77, pp.220. ⟨10.1140/epjc/s10052-017-4766-0⟩. ⟨in2p3-01390854⟩

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