The measurement of the Higgs self-coupling at the LHC: theoretical status

TL;DR

This work assesses the theoretical status of measuring the Higgs self-coupling at the LHC via Higgs pair production, detailing four main production modes and their higher-order QCD corrections (including NLO and NNLO where applicable). It provides energy-dependent cross sections (8–100 TeV), quantifies uncertainties from scales, PDFs, αs, and EFT approximations, and analyzes how sensitively each channel probes the trilinear coupling λHHH. The study finds that while gg→HH dominates and carries large theoretical uncertainties, vector boson fusion and Higgs-strahlung channels offer more precise prospects, with bbγγ and bbττ decay modes showing the most promise for extracting λHHH at high luminosity. Overall, the paper concludes that λHHH could be measured with roughly a factor-of-two precision in favorable channels at the HL-LHC, with greater potential at future higher-energy colliders.

Abstract

Now that the Higgs boson has been observed by the ATLAS and CMS experiments at the LHC, the next important step would be to measure accurately its properties to establish the details of the electroweak symmetry breaking mechanism. Among the measurements which need to be performed, the determination of the Higgs self-coupling in processes where the Higgs boson is produced in pairs is of utmost importance. In this paper, we discuss the various processes which allow for the measurement of the trilinear Higgs coupling: double Higgs production in the gluon fusion, vector boson fusion, double Higgs-strahlung and associated production with a top quark pair. We first evaluate the production cross sections for these processes at the LHC with center-of-mass energies ranging from the present $\sqrt s=8$ TeV to $\sqrt s=100$ TeV, and discuss their sensitivity to the trilinear Higgs coupling. We include the various higher order QCD radiative corrections, at next-to-leading order for gluon and vector boson fusion and at next-to-next-to-leading order for associated double Higgs production with a gauge boson. The theoretical uncertainties on these cross sections are estimated. Finally, we discuss the various channels which could allow for the detection of the double Higgs production signal at the LHC and the accuracy on the self-coupling that could be ultimately achieved.

Figures (17)

• Figure 1: Some generic Feynman diagrams contributing to Higgs pair production at hadron colliders.
• Figure 2: Generic diagrams contributing to the NLO corrections to $qq'\to HH qq'$. Shown are the LO diagram (upper left) and the NLO corrections for the upper quark line. The blob of the $VVHH$ vertex is a shortcut for the three diagrams shown in Figs. \ref{['processeslo']}b) and \ref{['VVHH-tensor']}.
• Figure 3: Diagrams contributing to the $VVHH$ vertex.
• Figure 4: Feynman diagrams contributing to the NLO QCD corrections for Drell--Yan production.
• Figure 5: Some Feynman diagrams contributing at NNLO QCD to Drell--Yan production.