JetCalibTools_Overview

This package contains all the jet calibration methods.

It is intended for physicists use and is also used in standard reconstruction.

Each calibration method (or "tool") is implemented in a separate C++ class inheriting the IJetCalibrator interface. They provide methods to

calibrate a given jet
return a calibrated copy,
store corrections as jet moment.
return only the computed corrections.

The corrections can be a simple scale factor or a set of numbers depending on the calibration tool.

JetCalibTools_Usage

All calibration tools are available as Athena tool (AthAlgTool), and some of them are also available in ARA.

It can be used as usual with ToolHandle, then example of use could be :

// get a calibrated copy : user must delete it when no more used.
Jet* myCalJet = myCalibTool->get_calibrated_copy(myUncalJet);
// store correction as jet moment :
myCalibTool->store_calibration_correction(myUncalJet);

JetCalibTools_Developers

Writing a calibration tool is writing a class inheriting IJetCalibrator. Some base implementation have been written, as JetCalibratorBase.

Developers can inherit JetCalibratorAthena or JetCalibratorARAAthena (also ARA availablilty but no DB support). All they have to do is to implement 2 JetCalibratorBase functions :

// Performs the calculation of corrections and store them in m_corrections
virtual bool  compute_corrections(const Jet* /*jet_in*/ ){return false;}
// Use the values calculated in m_corrections to correct the Jet 4mometum
virtual bool  correct_4mom(Jet* /*jet_in*/){return false;}

All the other functions of the interface will then be provided by the JetCalibratorBase class.

See also the wiki for more details : https://twiki.cern.ch/twiki/bin/view/AtlasProtected/JetCalibTools