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

Abstract

We present an implementation of W Zjj production via vector-boson fusion in the POWHEG BOX, a public tool for the matching of next-to-leading order QCD calculations with multi-purpose parton-shower generators. We provide phenomenological results for electroweak W Zjj production with fully leptonic decays at the LHC in realistic setups and discuss theoretical uncertainties associated with the simulation. We find that beyond the leading-order approximation the dependence on the unphysical factorization and renormalization scales is mild. The two tagging jets are furthermore very stable against parton-shower effects. However, considerable sensitivities to the shower Monte-Carlo program used are observed for central-jet veto observables.

Sleptons without hadrons

“…Categorically, we observe that the inclusion of MPI does not appreciably impact jet veto cross sections nor their uncertainties for both traditional, static jet vetoes and dynamic jet vetoes. In particular, we observe changes at the 5-10% level, inline with uncertainties and findings reported elsewhere [34]. For the dilepton and trilepton processes, we observe a comparable impact by including FxFx-merging; for H T -based vetoes, the impact of MPI and FxFx slightly compensate for one another.…”

“…Thus, we may conclude that cross sections forμ + Rμ − R production obtained from event generation at NLO+PS, either with or without a dynamic jet veto, are reliable estimates of the true rate. Similar reliability of NLO+PS predictions with static jet vetoes applied to SM diboson and weak boson scattering processes have been reported elsewhere [25,34]. Hence, for our purposes and for discovery purposes, NNLO and NNLL(threshold) terms in fixed order and resummed signal predictions can be ignored.…”

“…Among the several promising lines of such investigations are those that consider the impact of jet vetoes (i.e., the rejection of events featuring jets with a transverse momentum greater than some threshold p Veto T [15- * Electronic address: fuks@lpthe.jussieu.fr † Electronic address: knordstrom@lpthe.jussieu.fr ‡ Electronic address: richard.ruiz@uclouvain.be § Electronic address: sophie.williamson@kit.edu 19]) in measurements of and searches for heavy, colorless SM [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] and beyond the SM [35][36][37][38][39][40][41][42] states. Interestingly, recent studies of multilepton searches for heavy, colorless exotic particles have demonstrated that dynamic jet vetoes can significantly improve discovery potential [41,42].…”

Polarized vector boson scattering in the fully leptonic WZ and ZZ channels at the LHC

“…The measurements by the ATLAS and CMS Collaborations [4,5], as well as the recent calculation of the NLO EW and QCD corrections [26] and of parton shower effects [27] highlight a growing interest in the WZ scattering channel. In this section we investigate the phenomenology of polarized W + Z scattering in the fully leptonic decay channel at the LHC.…”

QCD and electroweak corrections to WZ scattering at the LHC

“…We also note that our calculation of QCD corrections is based on the full set of NLO diagrams including all interferences without approximation, i.e. we do not employ the so-called VBS approximation used in previous QCD calculations [11,12], which neglects colour exchange between the two incoming protons. While for the current experimental precision such approximations are most likely sufficient, in the future they might actually be inadequate, because they can fail at the level of 10% in differential distributions, as shown in Ref.…”