Spin Polarisation of $t\bar{t}\gamma \gamma$ production at NLO+PS with GoSam interfaced to MadGraph5_aMC@NLO

We present an interface between the multipurpose NLO Monte Carlo tool MadGraph5_aMC@NLO and the automated one-loop amplitude generator GoSam. As a first application of this novel framework, we compute the NLO corrections to $pp\to t\bar{t}H$ and $pp\to t\bar{t}\gamma \gamma$ matched to a parton shower. In the phenomenological analyses of these processes, we focus our attention on observables which are sensitive to the polarisation of the top quarks.