Color-singlet production at NNLO in MCFM

Abstract

We present the implementation of several colorsinglet 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 processesDecays 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 multiprocessor systems.

Multiboson interactions at the LHC

“…We also note that there are a number of multipurpose event generators used for the various multi-boson processes, such as VBFNLO (Arnold et al, 2009(Arnold et al, , 2011Baglio et al, 2014), MadGraph5 aMCNLO (Alwall et al, 2014), Powheg Box (Alioli et al, 2010Frixione et al, 2007;Melia et al, 2011;Nason, 2004;Nason and Zanderighi, 2014), Sherpa (Gleisberg et al, 2009;Gleisberg and Höche, 2008;Höche et al, 2009;Schumann and Krauss, 2008), and MCFM (Boughezal et al, 2017;Campbell and Ellis, 1999;Campbell et al, 2015Campbell et al, , 2011b. In the subsections below we concentrate on the current status of theoretical calculations rather than comparing the different MC capabilities.…”

W -boson plus jet differential distributions at NNLO in QCD

“…By now the application and validation of N -jettiness subtraction for one-jet processes has been discussed several times in the literature [13,23,24], and we do not review this topic here.…”

NNLO phenomenology with jettiness subtraction

“…We impose the following cuts on the final-state jet: p jet T > 30 GeV, |η jet | < 2.4 for Higgs+jet and |η jet | < 2.5 for W + +jet. For the Z + jet process we show a plot for the dependence of the ratio σ NNLO /σ NLO on the power corrections as a function of τ cut 1 and refer the reader to the corresponding paper for more phenomenological studies [7].…”

“…We review here the salient features of the jettiness-subtraction scheme for NNLO calculations, which was recently introduced in the context of the NNLO computation of W + boson and Higgs boson production in association with a jet [5,6,7]. We begin with the definition of N-jettiness, T N , a global event shape variable designed to veto final-state jets [9]:…”

“…Partial results for 2 → 2 processes such as inclusive jet production [2] and Higgs+jet production [3,4] are available. More recently complete results for Higgs+jet production [5], W + +jet production [6] and Z+jet production [7] were achieved using N-jettiness subtraction method [6,8,9,10]. The purpose of this contribution is to summarize the method and the results achieved for these two processes.…”