Study of quark and gluon jet substructure in Z+jet and dijet events from pp collisions



Measurements of jet substructure describing the composition of quark- and
gluon-initiated jets are presented. Proton-proton (pp) collision data at √
s = 13 TeV
collected with the CMS detector are used, corresponding to an integrated luminosity of
35.9 fb−1
. Generalized angularities are measured that characterize the jet substructure
and distinguish quark- and gluon-initiated jets. These observables are sensitive to the
distributions of transverse momenta and angular distances within a jet. The analysis is
performed using a data sample of dijet events enriched in gluon-initiated jets, and, for the
first time, a Z+jet event sample enriched in quark-initiated jets. The observables are measured in bins of jet transverse momentum, and as a function of the jet radius parameter.
Each measurement is repeated applying a “soft drop” grooming procedure that removes
soft and large angle radiation from the jet. Using these measurements, the ability of various
models to describe jet substructure is assessed, showing a clear need for improvements in
Monte Carlo generators.
Date made available13 Sep 2021


  • hep-ex


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