Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports the first measurement of polarized same-sign W boson pair production cross sections in proton-proton collisions at 13 TeV, using CMS data, setting upper limits and observing electroweak production with moderate significance.

Contribution

It provides the first experimental measurements of polarized same-sign W boson pairs, including cross sections and significance levels, in proton-proton collisions at 13 TeV.

Findings

Upper limit of 1.17 fb on longitudinally polarized W$^ ext{±}$W$^ ext{±}$ production

Electroweak production observed with 2.3 sigma significance

Data consistent with Standard Model predictions

Abstract

The first measurements of production cross sections of polarized same-sign W$^\pm$W$^\pm$ boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb$^{-1}$. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W$^\pm$W$^\pm$ scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88) fb is set on the production cross section for longitudinally polarized same-sign W$^\pm$W$^\pm$ boson pairs. The electroweak production of same-sign W$^\pm$W$^\pm$ boson pairs with at least one of the W bosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.