Search for Higgs boson pair production in the $\mathrm{b\bar{b}WW}$ decay channel with two leptons in the final state using proton-proton collision data at $\sqrt{s}$ = 13.6 TeV

Abstract

A search for Higgs boson pair production is presented, targeting final states where one Higgs boson decays to a pair of bottom quarks and the other Higgs boson decays to two W bosons, both of which decay leptonically, to an electron or a muon, and a neutrino. For the first time, the search is conducted with proton-proton collision data from the LHC at $\sqrt{s}$ = 13.6 TeV, recorded with the CMS detector in 2022 and 2023 and corresponding to an integrated luminosity of 62 fb$^{-1}$. The results are consistent with the standard model predictions. An upper limit of 12.0 times the standard model prediction at 95% confidence level is set on the Higgs boson pair production cross section, with an expected limit of 18.5. The results are also used to constrain the strength of the trilinear self-coupling of the Higgs boson, as well as of the quartic coupling between two Higgs bosons and two vector bosons.

Figures (9)

• Figure 1: Leading-order Feynman diagrams of ${ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace$ production in the ${ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace\text{F}$ production mode assuming top quarks in the fermion loop (top row) and in the $\text{VBF}$ production mode (bottom row) in the SM.
• Figure 2: Illustration of the event categorisation: SRs are depicted in red, background CRs in blue. Details of the NNs are described in the text. The binary NN output distributions (O) and the event yields (Y) in the CRs enter the final fit as sensitive observables.
• Figure 3: Invariant mass (upper left) and $p_{\mathrm{T}}$ (upper right) of the $\mathup{{{H}}{} _{ {}} ^{ {}}}$ candidate decaying to ${ \mathup{{{b}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{ \overline{ {{ \mathup{{{b}}{} _{ {}} ^{ {}}} }\xspace}}}{} _{ {}} ^{ {}}} }\xspace$, reconstructed as the invariant mass and $p_{\mathrm{T}}$, respectively, of the two jets with the highest $\mathup{{{b}}{} _{ {}} ^{ {}}}$ tagging score; invariant mass of the ${ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace$ system (lower left), reconstructed as the invariant mass of the two jets with the highest $\mathup{{{b}}{} _{ {}} ^{ {}}}$ tagging score, the two leptons, and $p_{\mathrm{T}}\xspace^\text{miss}$; and $p_{\mathrm{T}}$ of the jet with the highest $\mathup{{{b}}{} _{ {}} ^{ {}}}$ tagging score (lower right), for events in the analysis region observed in data (markers) and predicted by the background model (stacked histograms) prior to the fit to data. The ${ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace$ signal distributions in the ${ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace\text{F}$ and $\text{VBF}$ production channels as predicted in the SM, scaled to the total background yield for better visibility, are overlaid (solid lines). The uncertainty band represents the total systematic uncertainty.
• Figure 4: The $p_{\mathrm{T}}$ of the dilepton system in ${ \mathup{{{{ \mathup{{{e}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {+}}} }\xspace{ \mathup{{{{ \mathup{{{e}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {-}}} }\xspace$ events in the DY validation region before (left) and after (right) application of the DY corrections. The uncertainty band shows the total systematic uncertainty.
• Figure 5: Observed (points) and expected (filled histograms) yields in each discriminant (NN score or category yield) bin before (upper) and after (lower) the fit to data. The ${ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace$ signal distributions in the ${ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace\text{F}$ and $\text{VBF}$ production channels are overlaid (solid lines), scaled to the total background yield (top) or the observed upper limit for ${ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{g}}{} _{ {}} ^{ {}}} }\xspace\text{F}$ and the observed upper limit times 10 for $\text{VBF}$ (bottom). The uncertainty bands include the total uncertainty of the fit model. The lower panels show the ratio of the data to the expected background yields.