Observation of Electroweak Production of Same-Sign W Boson Pairs in the Two Jet and Two Same-Sign Lepton Final State in Proton-Proton Collisions at s=13  TeV

Abstract

The first observation of electroweak production of same-sign W boson pairs in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 35.9 fb^{-1} collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. Events are selected by requiring exactly two leptons (electrons or muons) of the same charge, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass. The observed significance of the signal is 5.5 standard deviations, where a significance of 5.7 standard deviations is expected based on the standard model. The ratio of measured event yields to that expected from the standard model at leading order is 0.90±0.22. A cross section measurement in a fiducial region is reported. Bounds are given on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators and on the production of doubly charged Higgs bosons.

Consistency of the standard model effective field theory

“…Yet those same dimension-six operators also induce anomalous triple gauge-boson couplings, on which the LHC has significantly extended the constraints from LEP [120], leaving room for aQGCs from dimension-eight operators. Deviations from the SM in these channels have been searched for at both ATLAS [27][28][29] and CMS [30][31][32];…”

“…Such deviations from the SM, induced by new high-scale physics, can be encoded as operators of higher mass dimension in an effective field theory (EFT) of the SM [22][23][24][25][26]. Using current measurements from the LHC [27][28][29][30][31][32], bounds have begun to be placed on the Wilson coefficients of some of the operators in the SMEFT; for a single example see Ref. [33].…”

Polarization fraction measurement in ZZ scattering using deep learning

“…Many VBS studies have been performed based on LHC data, including measurements of W ± W ± [1,2], W ± Z [3,4] and Zγ [5,6]. The topic of this paper is the channel ZZ → 4l.…”

Probing doubly and singly charged Higgs bosons at the pp collider HE-LHC

“…[34,35]. An alternative search where the H ±± is produced in association with two jets, i.e., vector boson fusion gives relaxed constraints [36,37]. Another scenario where doubly-charged Higgs decays to same-sign W ± boson pairs.…”