CMS-PAS-HIG-23-006

CMS-PAS-HIG-23-006
Constraints on the Higgs boson self-coupling with combination of single and double Higgs boson production
CMS Collaboration
28 November 2023

Abstract: A combination of Higgs boson (H) measurements and searches for the production of Higgs boson pairs (HH) is presented, aiming to constrain the H trilinear self-coupling $ \lambda_3 $, using the proton-proton collision data collected by the CMS experiment at $ \sqrt{s} = $ 13 TeV. The cross section of the main H production modes and the branching ratios of the principal decay channels depend on $ \lambda_3 $ because of next-to-leading-order electroweak corrections. On the other hand, the cross section of the HH production via gluon fusion and via vector boson fusion depend on $ \lambda_3 $ as well as on the H couplings to the top quark, and to vector bosons, respectively. The combination of event categories enriched in single-H and HH events allows the extraction of constraints on $ \kappa_\lambda $, defined as the value of $ \lambda_3 $ normalized to its standard model prediction, with fewer assumptions on the H couplings to the fermions and vector bosons. Values of $ \kappa_\lambda $ outside the interval $ -1.2 < \kappa_\lambda < $ 7.5 are excluded at 95% confidence level, which is compatible with the expected range of $ -2.0 < \kappa_\lambda < $ 7.7 under the assumption that all the other H couplings are at the standard model predicted values.
Links: CDS record (PDF) ; Physics Briefing ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to PLB. The superseded preliminary plots can be found here.

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