Non-local slicing approaches for NNLO QCD 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, ${\mathcal{T}}_0$, 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.

Comments: 34 pages, 8 figures, published version