Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy re-
sponse to jets of particles is derived for the ATLAS ex-
periment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is
measured and compared to the Monte Carlo simulation us-
ing proton-proton collisions at centre-of-mass energies of
√
s
=
900 GeV and 7 TeV collected during 2009 and 2010.
Then, using the decay of
K
s
and
Λ
particles, the calorimeter
response to specific types of particles (positively and nega-
tively charged pions, protons, and anti-protons) is measured
and compared to the Monte Carlo predictions. Finally, the
jet energy scale uncertainty is determined by propagating
the response uncertainty for single charged and neutral par-
ticles to jets. The response uncertainty is 2–5 % for central
isolated hadrons and 1–3 % for the final calorimeter jet en-
ergy scale.