Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at sqrts = 13 TeV

The first measurements of production cross sections of polarized same-sign $\mathrm{W}^{\pm}\mathrm{W^{\pm}}$ boson pairs in proton-proton collisions are reported. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of $137~\mathrm{fb}^{-1}$. 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. An observed (expected) 95$\%$ CL upper limit on the production cross section for longitudinally polarized same-sign $\mathrm{W}^{\pm}\mathrm{W^{\pm}}$ boson pairs of 1.17 (0.88) fb is reported, with the helicity eigenstates defined in the $\mathrm{W}^{\pm}\mathrm{W^{\pm}}$ center-of-mass reference frame. The electroweak production of same-sign $\mathrm{W}^{\pm}\mathrm{W^{\pm}}$ boson pairs with at least one of the $\mathrm{W}$ bosons longitudinally polarized, is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.