A measurement is presented of the electroweak vector boson scattering production of ZV (V = W, Z) boson pairs associated with two jets in proton-proton collisions at a center-of-mass energy of 13 TeV. The data, corresponding to an integrated luminosity of 138 fb$^{-1}$, were collected at the CERN LHC with the CMS detector during the 2016$-$2018 data-taking period. The analysis targets final states with a pair of isolated electrons or muons from Z boson decays and three or four jets, depending on the momentum of the vector boson that decays into quarks. Signal strength is measured for events characterized by a large invariant mass of two forward jets with a wide pseudorapidity gap between them. The electroweak production of ZV in association with two jets is measured with an observed (expected) significance of 1.3 (1.8) standard deviations. A combination of the analyses of ZV channel and the previously published WV channel in the lepton plus jets final state places constraints on effective field theory parameters that describe anomalous electroweak production of WW, WZ, and ZZ boson pairs in association with two jets. Several world best limits are set on anomalous quartic gauge couplings in terms of dimension-8 standard model effective field theory operators.
Distributions of DNN score for the data and post-fit backgrounds (stacked histograms), in the SRs of the ZV channel for the b tag (left) and the b veto (right) channels, for the resolved (merged) category in the first (second) row. The post-fit VBS EW ZV signal is shown overlaid as a red solid line. The overflow is included in the last bin. The lower panels show the ratios of the data to the pre-fit background prediction and post-fit background yield as red open squares and blue points, respectively. The gray band in the lower panels indicates the systematic component of the post-fit background uncertainty. The vertical bars on the data points represent statistical uncertainties. The last bin includes overflow.
Distributions of DNN score for the data and post-fit backgrounds (stacked histograms), in the SRs of the ZV channel for the b tag (left) and the b veto (right) channels, for the resolved (merged) category in the first (second) row. The post-fit VBS EW ZV signal is shown overlaid as a red solid line. The overflow is included in the last bin. The lower panels show the ratios of the data to the pre-fit background prediction and post-fit background yield as red open squares and blue points, respectively. The gray band in the lower panels indicates the systematic component of the post-fit background uncertainty. The vertical bars on the data points represent statistical uncertainties. The last bin includes overflow.
Distributions of DNN score for the data and post-fit backgrounds (stacked histograms), in the SRs of the ZV channel for the b tag (left) and the b veto (right) channels, for the resolved (merged) category in the first (second) row. The post-fit VBS EW ZV signal is shown overlaid as a red solid line. The overflow is included in the last bin. The lower panels show the ratios of the data to the pre-fit background prediction and post-fit background yield as red open squares and blue points, respectively. The gray band in the lower panels indicates the systematic component of the post-fit background uncertainty. The vertical bars on the data points represent statistical uncertainties. The last bin includes overflow.
The long-range collective flow of particles produced in oxygen-oxygen (OO) and neon-neon (NeNe) collisions is measured with the CMS detector at the CERN LHC. The data samples were collected at a center-of-mass energy per nucleon pair of 5.36 TeV, with integrated luminosities of 7 nb$^{-1}$ and 0.8 nb$^{-1}$ for OO and NeNe collisions, respectively. Two- and four-particle azimuthal correlations are measured over nearly five units of pseudorapidity. Significant elliptic ($v_2$) and triangular ($v_3$) flow harmonics are observed in both systems. The ratios of $v_n$ coefficients between NeNe and OO collisions reveal sensitivity to quadrupole correlations in the nuclear wave functions. Hydrodynamic models with $\textit{ab initio}$ nuclear structure inputs qualitatively reproduce the collision-overlap dependence of both the $v_n$ values and the NeNe to OO ratios. These measurements provide new constraints on hydrodynamic models for small collision systems and offer valuable input on the nuclear structure of $^{16}$O and $^{20}$Ne.
The $v_{2}\{2,\lvert\Delta\eta\rvert>2\}$, $v_{3}\{2,\lvert\Delta\eta\rvert>2\}$ and $v_{2}\{4\}$ values for charged particles as functions of centrality in OO collisions at 5.36 TeV.
The $v_{2}\{2,\lvert\Delta\eta\rvert>2\}$, $v_{3}\{2,\lvert\Delta\eta\rvert>2\}$ and $v_{2}\{4\}$ values for charged particles as functions of centrality in NeNe collisions at 5.36 TeV.
The $v_{2}\{2,\lvert\Delta\eta\rvert>2\}$ and $v_{2}\{4\}$ ratios for charged particles as functions of centrality in NeNe to OO collisions at 5.36 TeV.
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