PT Journal AU ATLAS Collaboration (Aad, Gea Aparisi Pozo, JA Bailey, AJ Cabrera Urban, S Castillo Gimenez, V Cerda Alberich, L Costa, MJ Escobar, C Estrada Pastor, O Fiorini, L Fullana Torregrosa, E Fuster, J Garcia, C Garcia Navarro, JE Gonzalez de la Hoz, S Gonzalvo Rodriguez, GR Guerrero Rojas, JGR Higon-Rodriguez, E Lacasta, C Lozano Bahilo, JJ Madaffari, D Mamuzic, J Marti-Garcia, S MiƱano M. Mitsou, VA Moreno Llacer, M Rodriguez Bosca, S Rodriguez Rodriguez, D Ruiz-Martinez, A Salt, J Santra, A Sayago Galvan, I Soldevila, U Sanchez, J Valero, A Valls Ferrer, JA Vos, M TI Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at root s=13 TeV with the ATLAS detector SO Journal of High Energy Physics JI J. High Energy Phys. PY 2023 BP 019 EP 56pp VL 06 IS 6 DI 10.1007/JHEP06(2023)019 LA English DE Hadron-Hadron Scattering; Top Physics AB A measurement of the top-quark mass (m(t)) in the t (t) over bar -> lepton+ jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass m(l mu) of the lepton, l (with l = e, mu), from the W-boson decay and the muon, mu, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb(-1) of root s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 +/- 0.39 (stat.) +/- 0.66 (syst.) +/- 0.25 (recoil) GeV, where the third uncertainty arises from changing the Pythia8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup. ER