Complete NLO corrections to W+W+ scattering and its irreducible background at the LHC

Abstract

The process pp → µ + ν µ e + ν e jj receives several contributions of different orders in the strong and electroweak coupling constants. Using appropriate event selections, this process is dominated by vector-boson scattering (VBS) and has recently been measured at the LHC. It is thus of prime importance to estimate precisely each contribution. In this article we compute for the first time the full NLO QCD and electroweak corrections to VBS and its irreducible background processes with realistic experimental cuts. We do not rely on approximations but use complete amplitudes involving two different orders at tree level and three different orders at one-loop level. Since we take into account all interferences, at NLO level the corrections to the VBS process and to the QCD-induced irreducible background process contribute at the same orders. Hence the two processes cannot be unambiguously distinguished, and all contributions to the µ + ν µ e + ν e jj final state should be preferably measured together.

Large NLO corrections in t t ¯ W ± $$ t\overline{t}{W}^{\pm } $$ and

“…To our knowledge, the only other calculation where all the NLO effects beyond the NLO QCD and NLO EW accuracy have been considered is the case of vector-boson-scattering (VBS) for two positively charged W bosons at the LHC including leptonic decays, namely the pp → µ + ν µ e + ν e jj process [26]. This complete-NLO prediction includes all the terms of O(α i s α j ) with i + j = 6, 7 and j ≥ 4, featuring both QCD-induced W + W + jj production and electroweak W + W + scattering.…”

“…In this article we want to give evidence that what has been found in ref. [26], i.e., large contributions from supposedly subleading corrections, is not an exception due to the particularities of this process [27] and standard VBS selection cuts, which reduce the "QCD backgrounds". It is rather a feature that may appear whenever the process considered…”

“…As a final remark, we want to remind the reader that the three known cases where NLO corrections from supposedly subleading EW contributions are large, pp → ttW ± , pp → tttt and pp → W + W + jj with leptonic W + decays [26], involve very different mechanisms. In ttW ± production it is the opening of tW → tW scattering via the real emission in the NLO 3 .…”

Electroweak corrections to vector-boson scattering

“…[11] and are inspired by the experimental searches for the VBS process [1,3,4]. For the centre-of-mass energy we have chosen 13 TeV.…”

“…In this proceedings contribution we summarize our calculation [11] of the complete NLO corrections to the full process pp → µ + ν µ e + ν e jj featuring in particular surprisingly large NLO EW corrections [12,13].…”