Measurements of the ratio of Z0 +JETS to Z0 cross-sections in the atlas detector at the Large Hadron Collider

The rate of decay of Z0 into electrons with associated jets is a valuable measurement for the commissioning of current-generation particle detectors at the Large Hadron Collider. It is both a candle for high-precision calibration and a background process for several searches. The measurement is also invaluable to determine the rate of associated jet production for the W+/- as the Z0 has no decays containing both electrons and jets.;In this dissertation the purpose behind the measurement is explained, then the Large Hadron Collider is briefly outlined. This is followed by a discussion of the goals of the ATLAS Experiment and makeup of the detector, including control system development engaged in as a contxibution to the commissioning of the machine by the author. Then a study of the differential efficiencies of the trigger is presented, the analysis of electrons in the ATLAS detector is discussed, and the theoretical background and predictions of the rate from simulated data are investigated and measured Finally, a measurement of the rate of associated jet production with 883 nb-1 of 7 TeV data from ATLAS is presented.