Parton-shower matching systematics in vector-boson-fusion WW production

Abstract

We perform a detailed analysis of next-to-leading order plus parton-shower matching in vector-boson-fusion WW production including leptonic decays. The study is performed in the Herwig 7 framework interfaced to VBFNLO 3, using the angular-ordered and dipole-based parton-shower algorithms combined with the subtractive and multiplicativematching algorithms.

Parton-shower effects in electroweak WZjj production at the next-to-leading order of QCD

“…In particular, PYTHIA8 and HERWIG7 offer the possibility of a local recoil dipole shower as an alternative to their respective default global recoil showers. The local recoil schemes have been shown to describe data for deepinelastic scattering [32] well, and have also been found to be advantageous for the theoretical description of VBS W ± W ± jj production [18] and for t-channel topquark production [33]. Both of these processes are similar to the VBS W Zjj process from the point of view of the parton shower as they share the same color flow between the initial and final state partons at LO.…”

“…While NLO-QCD corrections to VBS-induced ν + − + jj production at the LHC have been known for quite some time [14] and available in the form of a flexible parton-level Monte-Carlo program in the VBFNLO package [12], the matching of an NLO-QCD calculation with parton-shower programs has not been presented so far for this channel. Work in that direction has already been performed for the related W + W + jj, W + W − jj, and ZZjj VBS production modes [15,16,17,18]. For the W Zjj mode, however, no public implementation was available up to now.…”

An event generator for same-sign W-boson scattering at the LHC including electroweak corrections

“…The predictions at NLO QCD matched to QCD PS can be obtained from public tools like MadGraph5_aMC@NLO [72], the vbf_wp_wp package of POWHEG-BOX-V2, or using VBFNLO as a matrix-element provider interfaced to a Monte Carlo event generator, as done in Ref. [73] for VBS W + W − production. Note that the matrix elements from VBFNLO (that are also used in the vbf_wp_wp package of Powheg) have been obtained in the so-called VBS approximation [9,10,12].…”

Status and developments of event generators

“…Other features under development include NLO handling of loop-induced processes, an extended UFO Feynman rules [28] support, extended handling of event reweighting from weight vectors in HepMC files, improved top decays in the dipole shower, an interface to the HEJ program, and new models for soft interactions and diffraction. The already existing code will also be used for numerous physics studies, to explore and highlight the new possibilities [29].…”