Hadron energy reconstruction in ATLAS
Ongoing work (Per, Kerstin and C
Santoni and V Giangiobbe from C-F):
Analysis of combined test beam data:
reconstruction of energy of pions that
start to shower in TileCal, investigate
resolution and linearity.
Plans for future work
• Analysis of combined test beam data, in
particular combined calorimetry (time scale
for publication perhaps a year):
• Reconstruction of pion energy using
weighting methods, “bench mark method”,
weighting a la H1 using “TopoClusters”.
• Compare to MC, tune MC to real test
beam data.
• Jet reconstruction.
• In situ calibration.
From Tatra workshop on Calorimeter Calibration
HAD calibration (convener Peter Schacht)
HAD calibration session main focus will be on the
following topics:
* cluster reconstruction, identification, energy
* weighting scheme: experience with MC using
calibration hits (single pions, jets)
* testbeam results: H8 and H6 (EMEC/HEC +
o comparison with MC simulation
o GEANT 4 validation
o weighting scheme from MC pions
From Peter Loch, Tatra workshop on calorimeter calibration
Model II: More Local Calorimeter Calibration Motivations
Clustering, if correctly applied, even splits hadronic showers from single pions
into smaller pieces -> opens up a whole set of benchmarking and control features
using testbeam data!
you can directly monitor your calibration approach with real data before first
collisions in physics;
we have actually tried this before (not in ATLAS yet…):
fit calibration functions only depending on measurable quantities for clusters in
detailed testbeam simulations;
apply exactly these functions to the corresponding testbeam data (make sure you
are analyzing MC and data in the same way!) and verify approach by comparing basic
signal distributions, shower shapes, etc.;
after this validation apply the same functions to jets and test validity in physics
environment (see plot later this talk);
In situ + commissioning (convener Irene Vichou)
This session is aimed at exposing all the methods that
are envisaged to check and set the absolute scale
calibration of the calorimeters using physics events, after
their electromagnetic scale will have been set. These
methods include the use of the mass constraint of the Z–
>ee for the EM calorimeter and the W–>jet jet or the
balance in transverse momentum between a
Z(gamma) and a jet for the hadronic calorimeters.
Furthermore, the possibility to check the calibration
using cosmics or events typical of the initial
commissioning phase of the detector will be examined.
Working groups in ATLAS
• CTB LAr+Tile Pion analysis meetings (Claudio
• Hadron calibration working group (Peter
• Jets/ET-miss working group

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