Measurement of Missing Transverse Energy using the ATLAS Detector at the Large Hadron Collider

An important experimental signature for many physics processes to be studied with the ATLAS detector at the Large Hadron Collider (LHC) is missing transverse energy, $E_{T}^{Miss}$. The energy carried away by weakly or non-interacting particles such as neutrinos produced in particle collisions is inferred from an imbalance in the vector sum of energy measured transverse to the proton beam axis, the $E_{T}^{Miss}$. Many theories predict the production of new neutral, stable, and weakly interacting particles in LHC collisions. A signature of such a particle's production would be $E_{T}^{Miss}$. In this talk, the design of the ATLAS $E_{T}^{Miss}$ reconstruction software algorithms will be presented, along with performance studies using simulated and cosmic-ray data collected by the ATLAS detector.