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

TL;DR

This paper introduces a new interface between MadGraph5_aMC@NLO and GoSam, enabling NLO calculations for processes like top-antitop production with photons, with a focus on top polarization observables.

Contribution

It develops an automated framework combining MadGraph5_aMC@NLO and GoSam for NLO computations and applies it to top pair production with photons, emphasizing polarization effects.

Findings

NLO corrections computed for $pp \to t\bar{t}H$ and $pp \to t\bar{t}\gamma\gamma$

Analysis of polarization-sensitive observables

Framework facilitates future precise top physics studies

Abstract

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.