Non-local slicing approaches for NNLO QCD in MCFM

TL;DR

This paper implements NNLO QCD calculations for various processes in the MCFM Monte Carlo program using non-local slicing methods, improving the accuracy and flexibility of theoretical predictions for collider physics.

Contribution

It introduces the first implementation of NNLO corrections for several processes in MCFM using non-local slicing approaches, including decays of unstable bosons.

Findings

q_T slicing reduces power corrections compared to zero-jettiness for most processes

Fully differential Monte Carlo code with boson decays included

First NNLO implementation for W+W-, WZ, and ZZ in MCFM

Abstract

We present the implementation of several processes at Next-to-Next-to Leading Order (NNLO) accuracy in QCD in the parton-level Monte Carlo program MCFM. The processes treated are $pp\to H$, $W^\pm$, $Z$, $W^\pm H$, $ZH$, $W^\pm\gamma$, $Z\gamma$ and $\gamma\gamma$ and, for the first time in the code, $W^+W^-$, $W^\pm Z$ and $ZZ$. Decays of the unstable bosons are fully included, resulting in a flexible fully differential Monte Carlo code. The NNLO corrections have been calculated using two non-local slicing approaches, isolating the doubly unresolved region by cutting on the zero-jettiness, ${\cal T}_0$, or on $q_T$, the transverse momentum of the colour singlet final-state particles. We find that for most, but not all processes the $q_T$ slicing method leads to smaller power corrections for equal computational burden.