In situ determination of the scale and resolution of the jet energy measurements using Z0+jet events

In this note a method making use of Z0+jet events to calibrate the calorimetric jet energy measurements is described. It makes use only of measured quantities. Preliminary results obtained using ATLFAST are discussed. For light quarks the absolute value of the non linearity mu_p is smaller than 1% for 50GeV/c<pt(quark)<400GeV/c. For gluons mu_p is equal to-4.5% at 40GeV/c. At larger momenta the absolute value decreases and is smaller than 1% for pt(gluon)>180GeV/c. In the case of jets produced by quarks b, mu_p is about 2% for pt(b)<100GeV/c. The absolute value tends to be smaller than 1% for larger transverse momenta. The resolutions on the jet transverse momentum measurements were estimated within 1GeV/c.