On the impact of off-shell contributions on the top quark mass extraction in ttj events

In this contribution we present a systematic comparison of the full off-shell calculation for pp -> ttj in the dileptonic decay channel with a description based on the narrow width approximation. The aim of this study is to estimate the size of off-shell and non-resonant contributions to the shape of differential distributions, that will be utilized in the top quark mass extraction using the template fit method.