Color singlet production at NNLO in MCFM

TL;DR

This paper implements NNLO QCD calculations for several color-singlet processes in MCFM, enabling precise predictions for Higgs, Z, W, and diphoton production with full decay and differential analysis.

Contribution

It introduces the first implementation of NNLO corrections for multiple color-singlet processes in MCFM using the N-jettiness subtraction method.

Findings

Achieved fully differential NNLO predictions for key processes.

Analyzed systematic uncertainties from the N-jettiness regularization.

Optimized computational performance on multi-processor systems.

Abstract

We present the implementation of several color-singlet final-state processes at Next-to-Next-to Leading Order (NNLO) accuracy in QCD to the publicly available parton-level Monte Carlo program MCFM. Specifically we discuss the processes $pp\rightarrow H$, $pp\rightarrow Z$, $pp\rightarrow W$, $pp\rightarrow HZ$, $pp\rightarrow HW$ and $pp\rightarrow\gamma\gamma$. Decays of the unstable bosons are fully included, resulting in a flexible fully differential Monte Carlo code. The NNLO corrections have been calculated using the non-local $N$-jettiness subtraction approach. Special attention is given to the numerical aspects of running MCFM for these processes at this order. We pay particular attention to the systematic uncertainties due to the power corrections induced by the $N$-jettiness regularization scheme and the evaluation time needed to run the hybrid openMP/MPI version of MCFM at NNLO on multi-processor systems.