Model-independent measurement of the Higgs boson associated production with two jets and decaying to a pair of W bosons in proton-proton collisions at $\sqrt{s}$ = 13 TeV

Abstract

A model-independent measurement of the differential production cross section of the Higgs boson decaying into a pair of W bosons, with a final state including two jets produced in association, is presented. In the analysis, events are selected in which the decay products of the two W bosons consist of an electron, a muon, and missing transverse momentum. The model independence of the measurement is maximized by making use of a discriminating variable, developed through machine learning, that is agnostic to the signal hypothesis. The analysis is based on proton-proton collision data at $\sqrt{s}$ = 13 TeV collected with the CMS detector from 2016$-$2018, corresponding to an integrated luminosity of 138 fb$^{-1}$. The production cross section is measured as a function of the difference in azimuthal angle between the two jets. The differential cross section measurements are used to constrain Higgs boson couplings within the standard model effective field theory framework.

Figures (14)

• Figure 1: Normalized VBF differential cross section as a function of the signed azimuthal angle difference between the two jets, with the Higgs boson mass assumed to be 125$\,\text{Ge\spaceV}$. Different hypotheses are superimposed corresponding to a mixed $CP$ scenario, a pure $CP$-even AC, a pure $CP$-odd AC, and an SM coupling in the HVV vertex.
• Figure 2: Normalized distributions of $\mathcal{D}_\mathrm{VBF}$ (left) and $\mathcal{D}_\mathrm{ggH}$ (right), evaluated on signal and background events using the ADNNs trained on even-numbered MC events. The signal predictions are displayed as an envelope representing the range of algorithm outputs across all signal hypotheses included in the training. The background class contributions from SM ggH (left) and SM VBF (right) events are highlighted using dashed lines. For $\mathcal{D}_\mathrm{VBF}$, the background class contains ggH events according to the SM proportion, and the corresponding contribution is rescaled by a factor of 50 to enhance visibility in the plot; for $\mathcal{D}_\mathrm{ggH}$, the background class contains 50% VBF events.
• Figure 3: Post-fit $\mathcal{D}_\mathrm{VBF}$ distributions in the $\Delta\Phi_\mathrm{{jj}}$ bins of the SR for the 2016--2018 data set, corresponding to fit configuration 3. Systematic uncertainties are shown as dashed gray bands. The pre-fit signal is shown superimposed as a dotted line, while the post-fit signal is included in the stacked histograms on top of the background templates. A uniform binning is applied for visualization, with the true binning range indicated on the $x$ axis. The binning scheme optimized for the 2018 data set is used. The lower panel shows the ratio of data to the total post-fit expected yield (Data/Exp.), where the signal contribution is included in the expectation.
• Figure 4: Post-fit $\mathcal{D}_\mathrm{VBF,ggH}$ distributions in the $\Delta\Phi_\mathrm{{jj}}$ bins of the SR for the 2016--2018 data set, corresponding to fit configuration 1. The 2D distribution is unrolled into a 1D histogram, where the $x$ axis represents the $\mathcal{D}_\mathrm{VBF}$ variable. A uniform binning is adopted for visualization. The boundaries of the $\mathcal{D}_\mathrm{ggH}$ intervals are marked by dashed black vertical lines, with the corresponding ranges explicitly labeled. Within each $\mathcal{D}_\mathrm{ggH}$ interval, the binning reflects the $\mathcal{D}_\mathrm{VBF}$ subdivisions, and the true $\mathcal{D}_\mathrm{VBF}$ ranges are indicated on the $x$ axis. Systematic uncertainties are shown as dashed gray bands. The pre-fit signal is shown superimposed as a dotted line, while the post-fit signal is included in the stacked histograms on top of the background templates. The binning scheme optimized for the 2018 data set is used. The lower panel shows the ratio of data to the total post-fit expected yield (Data/Exp.), where the signal contribution is included in the expectation.
• Figure 5: Measured fiducial cross section of the VBF and ggH production processes. Colored markers represent the extracted cross section values from data, with error bars showing the combined statistical and systematic uncertainties: red for VBF, light blue for ggH, and violet for the sum of VBF + ggH. The gray bands indicate the statistical uncertainties. The colored histogram corresponds to the expected SM prediction, simulated with powheg + JHUGen + pythia generators. The lower panel displays the ratio of the measured values to the SM expectation.