Effects of genuine dimension-six Higgs operators

TL;DR

This work analyzes genuine dimension-six Higgs operators that are not tightly constrained by precision data and how they modify Higgs kinetic terms, masses, gauge couplings, and self-interactions. By introducing a pair of Higgs-only operators with parameters $a_1$ and $a_2$, the authors map these effects onto an extended potential and derive how observables like Higgs production cross sections depend on these anomalous couplings. They evaluate the sensitivity of future $e^+e^-$ linear colliders (at $\sqrt{s}=500$–$800$ GeV and up to multi-TeV with CLIC) to $a_1$ and $a_2$ through single and double Higgs production, finding typical reach around $\Delta a_1 \sim 0.005$ and $\Delta a_2 \sim 0.1$ at 500 GeV, improving at higher energies; these translate into new-physics scales $\Lambda$ of several TeV for $f_i\sim1$. The study highlights that precision collider measurements can probe Higgs-sector extensions well before direct production of new states, with linear colliders offering superior sensitivity to Higgs self-interactions compared to the LHC.

Abstract

We systematically discuss the consequences of genuine dimension-six Higgs operators. These operators are not subject to stringent constraints from electroweak precision data. However, they can modify the couplings of the Higgs boson to electroweak gauge bosons and, in particular, the Higgs self-interactions. We study the sensitivity to which those couplings can be probed at future $\ee$ linear colliders in the sub-TeV and in the multi-TeV range. We find that for $\sqrt s=500$ GeV with a luminosity of 1 ab$^{-1}$ the anomalous $WWH$ and $ZZH$ couplings may be probed to about the 0.01 level, and the anomalous $HHH$ coupling to about the 0.1 level.

Figures (9)

• Figure 1: Cross sections for single Higgs boson production versus $a_1$ at $\sqrt s=500$ and 800 GeV for (a) Higgs-strahlung, (b) $WW$-fusion, and (c) $ZZ$-fusion.
• Figure 2: Combined statistical accuracy on $a_1$ with an integrated luminosity of 1 ab$^{-1}$ for $\sqrt s=500$ GeV and $800$ GeV, using the Higgs-strahlung, the $WW$-fusion and $ZZ$-fusion channels, as described in the text.
• Figure 3: Cross sections for double Higgs production at $\sqrt s=500$ and 800 GeV versus $a_1$ and $a_2$ by (a) Higgs-strahlung, (b) $WW$-fusion.
• Figure 4: Combined statistical accuracy on $a_2$ with an integrated luminosity of 1 ab$^{-1}$ for $\sqrt s=500$ GeV and $800$ GeV, using the Higgs-strahlung and the $WW$-fusion channels, as described in the text.
• Figure 5: Cross sections at $\sqrt s=3$ and 5 TeV (a) for single Higgs boson production versus $a_{1}$ via $WW$-fusion and (b) via $ZZ$-fusion; (c) for double Higgs boson production versus $a_{1,2}$ via $WW$-fusion and (d) via $ZZ$-fusion.