210
6 Summary
for jet substructure analyses. These include hit efficiencies in the tracking detectors,
the reconstruction of tracks in dense environments, the clustering and calibration of
energy deposits in granular calorimeters and the possibility to combine tracking and
calorimetric measurements. The influence of in-time and out-of-time pileup is an
important aspect that needs to be corrected for. Calibrations of the jet energy scale
and resolution are as important as calibrations of the jet mass scale and resolution.
In experimental analyses, jet collections with different distance parameters are frequently used, such that corrections for different types of jets need to be derived. The
performance of jet substructure taggers needs to be measured in dedicated samples
of real collision data in order to validate their expected performance from simulation.
A reliable prediction of jet substructure observables by event generators is key to
precise measurements, such that the tuning of free parameters to experimental data
is another important aspect.
Measurements that have tested our understanding of jet substructure constitute
unfolded measurements of the groomed and ungroomed jet mass in light quark and
gluon jets. These help to understand the regions of validity in the approximations
made in event generators for describing jet substructure observables. These measurements also show the efficacy of grooming algorithms. Measurements of the jet mass
in soft-drop groomed jets show good agreement with analytic calculations in their
region of validity, establishing confidence in these calculations. This opens the possibility for a precise determination of the strong coupling constant from jet substructure
measurements. Differential measurements of the radiation pattern in light quark and
gluon jets show an overall good description of the data in regions dominated by both,
perturbative and non-perturbative effects. Together with measurements of (charged)
particle multiplicities, these measurements will help to improve the modelling of jet
substructure observables in future tunes of event generators, where gluon-initiated
jets are less well constrained than quark initiated jets. Unfolded jet mass measurements of W and t jets have shown a reliable calibration and modelling of fully merged
two- and three-prong decays. The measurements of t jets have enabled the determination of the top quark mass from the production of highly boosted top quarks.
Unfolded measurements of jet substructure observables in resolved, partially and
fully merged t decays resulted in comprehensive data that can be used for improvements in the description of additional radiation and the modelling of colour flow and
other non-perturbative effects in tt production.
Developments of jet substructure techniques have enabled a number of SM measurements at high p T . Measurements of electroweak vector boson production in
V +jets processes have to cope with large backgrounds from multijet production.
Conversely, studies of diboson production have to reduce V +jets processes for reliable measurements. Efficient substructure taggers, in combination with methods for
estimating the non-resonant backgrounds, enabled first studies of these processes in
hadronic channels and allowed to constrain anomalous production mechanisms. Jet
substructure techniques are key to measurements of high- p T Higgs boson production
in bb and cc decays. Developments of b and c flavour tagging in dense environments
have been crucial for first results in these channels. In studies of tt production, top
quark tagging has been indispensable for measurements at high p T . A combination
6 Summary
for jet substructure analyses. These include hit efficiencies in the tracking detectors,
the reconstruction of tracks in dense environments, the clustering and calibration of
energy deposits in granular calorimeters and the possibility to combine tracking and
calorimetric measurements. The influence of in-time and out-of-time pileup is an
important aspect that needs to be corrected for. Calibrations of the jet energy scale
and resolution are as important as calibrations of the jet mass scale and resolution.
In experimental analyses, jet collections with different distance parameters are frequently used, such that corrections for different types of jets need to be derived. The
performance of jet substructure taggers needs to be measured in dedicated samples
of real collision data in order to validate their expected performance from simulation.
A reliable prediction of jet substructure observables by event generators is key to
precise measurements, such that the tuning of free parameters to experimental data
is another important aspect.
Measurements that have tested our understanding of jet substructure constitute
unfolded measurements of the groomed and ungroomed jet mass in light quark and
gluon jets. These help to understand the regions of validity in the approximations
made in event generators for describing jet substructure observables. These measurements also show the efficacy of grooming algorithms. Measurements of the jet mass
in soft-drop groomed jets show good agreement with analytic calculations in their
region of validity, establishing confidence in these calculations. This opens the possibility for a precise determination of the strong coupling constant from jet substructure
measurements. Differential measurements of the radiation pattern in light quark and
gluon jets show an overall good description of the data in regions dominated by both,
perturbative and non-perturbative effects. Together with measurements of (charged)
particle multiplicities, these measurements will help to improve the modelling of jet
substructure observables in future tunes of event generators, where gluon-initiated
jets are less well constrained than quark initiated jets. Unfolded jet mass measurements of W and t jets have shown a reliable calibration and modelling of fully merged
two- and three-prong decays. The measurements of t jets have enabled the determination of the top quark mass from the production of highly boosted top quarks.
Unfolded measurements of jet substructure observables in resolved, partially and
fully merged t decays resulted in comprehensive data that can be used for improvements in the description of additional radiation and the modelling of colour flow and
other non-perturbative effects in tt production.
Developments of jet substructure techniques have enabled a number of SM measurements at high p T . Measurements of electroweak vector boson production in
V +jets processes have to cope with large backgrounds from multijet production.
Conversely, studies of diboson production have to reduce V +jets processes for reliable measurements. Efficient substructure taggers, in combination with methods for
estimating the non-resonant backgrounds, enabled first studies of these processes in
hadronic channels and allowed to constrain anomalous production mechanisms. Jet
substructure techniques are key to measurements of high- p T Higgs boson production
in bb and cc decays. Developments of b and c flavour tagging in dense environments
have been crucial for first results in these channels. In studies of tt production, top
quark tagging has been indispensable for measurements at high p T . A combination