The Gauge-Higgs Legacy of the LHC Run I

Abstract: The effective Lagrangian expansion provides a framework to study effects of new physics at the electroweak scale. To make full use of LHC data in constraining higher-dimensional operators we need to include both the Higgs and the electroweak gauge sector in our study. We first present an analysis of the relevant di-boson production LHC results to update constraints on triple gauge boson couplings. Our bounds are several times stronger than those obtained from LEP data. Next, we show how in combination with Higgs measurements the triple gauge vertices lead to a significant improvement in the entire set of operators, including operators describing Higgs couplings.

• The paper demonstrates that combining Higgs production and di-boson data yields strong constraints on dimension-six operators beyond the Standard Model.
• It employs an effective field theory method to update triple gauge boson couplings, achieving more precise limits than previous LEP measurements.
• Enhanced limits on Wilson coefficients clarify Higgs-gauge interactions and inform future collider strategies in probing new physics.

Overview of "The Gauge-Higgs Legacy of the LHC Run I"

The paper "The Gauge-Higgs Legacy of the LHC Run I" focuses on the analysis of the LHC Run I data to investigate effects of new physics at the electroweak scale using the effective Lagrangian expansion framework. This study is essential as it combines precision measurements from both Higgs production and electroweak gauge boson pair production to provide constraints on higher-dimensional operators which characterize new physics beyond the Standard Model (SM).

Key Objectives and Methodology

The research aims to leverage LHC data maximally to constrain higher-dimensional operators and elucidate the interaction between the Higgs boson and gauge sectors. A significant aspect of the work involves updating constraints on triple gauge boson couplings (TGVs) using di-boson production results. Notably, the bounds obtained from LHC Run I data are stronger than those from LEP data, indicating improvements in constraining new physics effects.

An effective field theory approach is employed, parameterizing the low-energy effects of SM extensions by constructing an effective Lagrangian. This approach involves determining coefficients for dimension-six operators, notably those impacting Higgs interactions and triple gauge boson vertices.

Results and Numerical Highlights

The paper presents comprehensive results from LHC Run I, markedly advancing previous constraints. Specifically, it provides the following limits on Wilson coefficients expressed in terms of dimension-six operators:

• For $f_W/\Lambda^2$, the 95% CL range is $[-1.5, 6.3]$ TeV$^{-2}$.
• For $f_B/\Lambda^2$, the 95% CL range is $[-14.3, 15.9]$ TeV$^{-2}$.
• For $f_{WWW}/\Lambda^2$, the 95% CL range is $[-2.4, 3.2]$ TeV$^{-2}$.

Through detailed analysis of multiple di-boson channels and Higgs data from the LHC Run I, the study enhanced the precision of TGVs compared to LEP results. The combined analysis resulted in stronger constraints on the associated dimension-six operators, effectively eliminating secondary solutions and improving the consistency with SM predictions.

Theoretical and Practical Implications

The research has significant theoretical implications, particularly concerning the electroweak symmetry breaking mechanism. By examining potential deviations in TGVs and Higgs couplings, the study offers insights into possible extensions or alternatives to the SM. Practically, it improves the precision of determining new physics scales, paving the way for identifying signatures of new physics in future LHC runs and other collider experiments.

Future Directions

Looking forward, ongoing and forthcoming LHC analyses could benefit from similar combined approaches. The framework outlined can serve as a benchmark for more extensive studies incorporating higher-order operators or integrating new data from future LHC runs. Moreover, refining the sensitivities and incorporating updated theoretical models will aid in enhancing the robustness of constraints derived from collider data.

The paper sets a precedent for how effective Lagrangian expansion can be utilized to interpret collider data, thus contributing significantly to our understanding of the Higgs-gauge interactions and their role in new physics explorations.