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

ATLAS Publications, T.M. Carter, M. Faucci Giannelli, A. Hasib, M.P. Heath Heath, S. Palazzo, A. Søgaard, E.P. Takeva, A.J. Taylor, N. Themistokleous, E.M. Villhauer

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Several observables sensitive to the fragmentation of b quarks into b hadrons are measured using 36  fb-1 of 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 tt¯ 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 e+e- collider experiments in which the b quarks originate from a color singlet Z/γ*.
Original languageEnglish
Article number032008
Pages (from-to)1-33
Number of pages33
JournalPhysical Review D
Issue number3
Publication statusPublished - 9 Aug 2022


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