Event Generation for the Run 2 W Mass Measurement

An important contribution to the systematic uncertainty on the Run II W mass measurement comes from the modelling of W boson production and decay. This source of uncertainty will be one of the most significant in future high-statistics measurements. We describe the event generation used for constructing templates for fitting the W mass, including the relevant physics processes influencing the lineshapes of the fit variables. We present systematic uncertainties deriving from the production model, including final state photon radiation and $p_{T}^{W}$.