Modifications to the Properties of the Higgs Boson

TL;DR

The paper investigates how SU(3)×SU(2)×U(1) invariant dimension-six operators at the TeV scale can significantly modify Higgs production and loop-induced decays, particularly through gg→h, h→γγ, and h→γZ, even when new physics lies well above the electroweak scale. By deriving rate ratios that depend on operator coefficients (c_G, c_W, c_B, c_WB, and their CP-odd counterparts) and SM loop functions, the authors illustrate that sizable deviations from Standard Model expectations are possible at plausible TeV scales. They discuss expected operator magnitudes from naive dimensional analysis and explore how such operators could influence gauge coupling unification via threshold effects, arguing that coefficients around 0.1 are both reasonable and impactful. The work emphasizes that Higgs channels at the LHC, especially γγ and γZ in the sub‑WW region and gg-driven production, provide a powerful, mostly model-independent test for this class of new physics and its connection to unification.

Abstract

We explore the impact of new SU(3)XSU(2)XU(1) invariant interactions characterized by a scale of order a TeV on Higgs boson properties. The Higgs production rate and branching ratios can be very different from their standard model values. We also discuss the possibility that these new interactions contribute to acceptable unification of the gauge couplings.

Figures (5)

• Figure 1: The standard model $h \to gg$ amplitude $I^g$ given by Eq. (\ref{['igamp']}) plotted as a function of the Higgs mass.
• Figure 2: The standard model $h \to \gamma\gamma$ amplitude $I^\gamma$ given by Eq. (\ref{['igamma']}) (solid curve) and the $h \to \gamma Z$ amplitude $I^Z$ given by Eq. (\ref{['izamp']}) (dashed curve) plotted as a function of the Higgs mass.
• Figure 3: The ratio of the $gg \to h$ cross-section to its standard model value as a function of $c_G$ for $m_h=120$ GeV (dashed red), $m_h=140$ GeV (solid black) and $m_h=160$ GeV (dotted blue). The variation with Higgs mass is very small.
• Figure 4: The ratio of the $h \to \gamma\gamma$ decay rate to its standard model value as a function of $c_{\gamma\gamma}$ for $m_h=120$ GeV (dashed red), $m_h=140$ GeV (solid black) and $m_h=160$ GeV (dotted blue).
• Figure 5: The ratio of the $h \to \gamma Z$ decay rate to its standard model value as a function of $c_{\gamma Z}$ for $m_h=120$ GeV (dashed red), $m_h=140$ GeV (solid black) and $m_h=160$ GeV (dotted blue).