Jets are one of the most prominent physics signatures of high energy proton
proton (p-p) collisions at the Large Hadron Collider (LHC). They are key
physics objects for precision measurements and searches for new phenomena. This
review provides an overview of the reconstruction and calibration of jets at
the LHC during its first Run. ATLAS and CMS developed different approaches for
the reconstruction of jets, but use similar methods for the energy calibration.
ATLAS reconstructs jets utilizing input signals from their calorimeters and use
charged particle tracks to refine their energy measurement and suppress the
effects of multiple p-p interactions (pileup). CMS, instead, combines
calorimeter and tracking information to build jets from particle flow objects.
Jets are calibrated using Monte Carlo (MC) simulations and a residual in situ
calibration derived from collision data is applied to correct for the
differences in jet response between data and Monte Carlo. Large samples of
dijet, Z+jets, and photon+jet events at the LHC allowed the calibration of jets
with high precision, leading to very small systematic uncertainties. Both ATLAS
and CMS achieved a jet energy calibration uncertainty of about 1% in the
central detector region and for jets with transverse momentum pT>100 GeV. At
low jet pT, the jet energy calibration uncertainty is less than 4%, with
dominant contributions from pileup, differences in energy scale between quark
and gluon jets, and jet flavor composition.Comment: Article submitted to the International Journal of Modern Physics A
(IJMPA) as part of the special issue on the "Jet Measurements at the LHC",
editor G. Dissertor
