Gravitational Interaction of Higgs Boson and Weak Boson Scattering

TL;DR

This paper investigates the gravitational interaction of the Higgs boson through a nonminimal coupling, deriving bounds and proposing experimental probes at the LHC to detect effects of this coupling.

Contribution

It introduces a gauge-invariant effective interaction framework for Higgs-gravity coupling and derives new unitarity bounds and experimental signatures at the LHC.

Findings

Derived a stronger unitarity bound on the Higgs gravitational coupling  in Einstein frame.

Showed that  affects weak boson scattering cross sections at TeV scale.

Proposed a novel LHC method to probe Higgs-gravity coupling  via weak boson scattering.

Abstract

With the LHC discovery of a 125 GeV Higgs-like boson, we study gravitational interaction of the Higgs boson via the unique dimension-4 operator involving Higgs doublet and scalar curvature, $\,\xi H^\dag H R\,$, with nonminimal coupling $\,\xi\,$. This Higgs portal term can be transformed away in Einstein frame and induces gauge-invariant effective interactions in the Higgs sector. We study the weak boson scattering in Einstein frame, and explicitly demonstrate the longitudinal-Goldstone boson equivalence theorem in the presence of $\,\xi\,$ coupling. With these, we derive unitarity bound on the Higgs gravitational coupling $\,\xi\,$ in Einstein frame, which is stronger than that inferred from the current LHC Higgs measurements. We further study $\xi$-dependent weak boson scattering cross sections at TeV scale, and propose a new LHC probe of the Higgs-gravity coupling $\,\xi\,$ via weak boson scattering experiments.