Modeling the Mobility and Lorentz angle for the ATLAS Pixel Detector

The electron and hole mobility plays a key role in determining the cluster shape in the ATLAS silicon pixel detectors. A proper model of the mobility is therefore important for properly simulating track reconstruction. Various mobility models are studied in the ATLAS simulation framework to determine their predictions for Run 2 conditions. One way to probe the mobility directly in data is to study the Lorentz angle. Measurements of the Lorentz angle are used to assess the mobility model quality. As a result of these studies, the default mobility model is updated from the Run 1 default.