Jet Energy Reconstruction in the ATLAS Barrel Calorimeters Using Combined Beam Test Data

The method of the parton energy reconstruction in the barrel part ofthe ATLAS calorimeter system (electromagnetic LAr and hadronic Tilecalorimeter) is presented. The results are based on the experimentaldata obtained during the combined LAr+Tilecal beam test in April1996 - particles of gluon and light quark jets generated by Pythiaand Jetset are replaced by the electron and hadron events. The applied method recovers the linearity within $pm 0.5%$ up to 1~TeV and improves the energy resolution. The implications for the LVL1 trigger are discussed as well.