Abstract
Searches for resonant and nonresonant pair-produced Higgs bosons (HH) decaying respectively into ℓνℓν, through either W or Z bosons, and mathrm{b}overline{mathrm{b}} are presented. The analyses are based on a sample of proton-proton collisions at sqrt{s}=13 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb−1. Data and predictions from the standard model are in agreement within uncertainties. For the standard model HH hypothesis, the data exclude at 95% confidence level a product of the production cross section and branching fraction larger than 72 fb, corresponding to 79 times the standard model prediction. Constraints are placed on different scenarios considering anomalous couplings, which could affect the rate and kinematics of HH production. Upper limits at 95% confidence level are set on the production cross section of narrow-width spin-0 and spin-2 particles decaying to Higgs boson pairs, the latter produced with minimal gravity-like coupling.
Highlights
Data and predictions from the standard model are in agreement within uncertainties
For the standard model HH hypothesis, the data exclude at 95% confidence level a product of the production cross section and branching fraction larger than 72 fb, corresponding to 79 times the standard model prediction
Indirect effects at the electroweak scale arising from beyond the standard model (BSM) phenomena at a higher scale can be parameterised in an effective field theory framework [22,23,24] by introducing coupling modifiers for the SM parameters involved in HH production, namely κλ = λ/λSM for the Higgs boson self-coupling λ and κt = yt/ytSM for the top quark Yukawa coupling yt
Summary
The central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic field of 3.8 T. Feynman diagrams for Higgs boson pair production via gluon fusion in the SM. The coupling modifiers for the Higgs boson self-coupling and the top quark Yukawa coupling are denoted by κλ and κt, respectively. Strip tracker, a lead tungstate crystal electromagnetic calorimeter (ECAL), and a brass and scintillator hadron calorimeter, each composed of a barrel and two endcap sections. Forward calorimeters extend the pseudorapidity coverage provided by the barrel and endcap detectors. Muons are detected in gas-ionisation chambers embedded in the steel flux-return yoke outside the solenoid. A more detailed description of the CMS detector, together with a definition of the coordinate system used and the relevant kinematic variables, can be found in ref. A more detailed description of the CMS detector, together with a definition of the coordinate system used and the relevant kinematic variables, can be found in ref. [40]
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