Energy-Enhanced Dimension Eight SMEFT Effects in VBF Higgs production

TL;DR

This paper investigates the impact of dimension-eight SMEFT operators on VBF Higgs production at the LHC, revealing that these effects could be significant under certain conditions and are influenced by kinematic suppression.

Contribution

It introduces a comprehensive analysis of dimension-eight SMEFT operators in VBF Higgs production using the geometric SMEFT framework, extending beyond previous studies limited to dimension-six operators.

Findings

Higher-dimensional operators are suppressed by VBF kinematics, requiring lower new physics scales for detection.

LEP constraints limit the impact of dimension-six operators, making dimension-eight effects more relevant.

Dimension-eight operators can also affect associated Higgs production processes, depending on analysis cuts.

Abstract

We study Higgs boson production via vector boson fusion at the LHC, focusing on the process $pp \to H + jj$ and capturing the leading energy-enhanced contributions within the Standard Model Effective Field Theory (SMEFT) up to order $1/\Lambda^4$. Employing energy-scaling arguments, we predict the magnitude of each higher-dimensional operator's contribution. Utilizing the geometric formulation of SMEFT, our analysis incorporates dimension-eight operators not previously considered. We find that the kinematics of vector boson fusion - characterized by two highly forward jets - tend to suppress contributions from higher-dimensional operators, requiring a lower scale $\Lambda$ for SMEFT effects to become observable. This suggests that the SMEFT remains valid for lower $\Lambda$ than expected. Combined with the fact that LEP constrains the dimension-six operators with the most considerable impact on vector boson fusion, a regime exists where dimension-eight operators can have significant effects. In many cases, these dimension-eight operators also influence associated production processes like $pp \to H V(jj)$, though differences in analysis cuts and kinematics mean this is not always the case. Our findings provide insights that could refine the search for SMEFT signals in collider experiments.