Several observables sensitive to the fragmentation of b quarks into b hadrons are measured using 36 fb−1 of sqrt(s) = 13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Jets containing b hadrons are obtained from a sample of dileptonic t¯t events, and the associated set of charged particle tracks is separated into those from the primary pp interaction vertex and those from the displaced b-decay secondary vertex. This division is used to construct observables that characterize the longitudinal and transverse momentum distributions of the b hadron within the jet. The measurements have been corrected for detector effects and provide a test of heavy-quark-fragmentation modeling at the LHC in a system where the top-quark decay products are color connected to the proton beam remnants. The unfolded distributions are compared with the predictions of several modern Monte Carlo parton-shower generators and generator tunes, and a wide range of agreement with the data is observed, with p values varying from 5 × 10−4 to 0.98. These measurements complement similar measurements from eþe− collider experiments in which the b quarks originate from a color singlet Z=γ.

Measurements of jet observables sensitive to quark fragmentation in events at the LHC with the ATLAS detector

G Chiodini;E Gorini;F Gravili;L Longo;M Primavera;M Reale;E Schioppa;S Spagnolo;A Ventura;
2022

Abstract

Several observables sensitive to the fragmentation of b quarks into b hadrons are measured using 36 fb−1 of sqrt(s) = 13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Jets containing b hadrons are obtained from a sample of dileptonic t¯t events, and the associated set of charged particle tracks is separated into those from the primary pp interaction vertex and those from the displaced b-decay secondary vertex. This division is used to construct observables that characterize the longitudinal and transverse momentum distributions of the b hadron within the jet. The measurements have been corrected for detector effects and provide a test of heavy-quark-fragmentation modeling at the LHC in a system where the top-quark decay products are color connected to the proton beam remnants. The unfolded distributions are compared with the predictions of several modern Monte Carlo parton-shower generators and generator tunes, and a wide range of agreement with the data is observed, with p values varying from 5 × 10−4 to 0.98. These measurements complement similar measurements from eþe− collider experiments in which the b quarks originate from a color singlet Z=γ.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11587/473086
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