Constraining anomalous HVV interactions at proton and lepton colliders (1309.4819v3)

Abstract: In this paper, we study the extent to which CP parity of a Higgs boson, and more generally its anomalous couplings to gauge bosons, can be measured at the LHC and a future electron-positron collider. We consider several processes, including Higgs boson production in gluon and weak boson fusion and production of a Higgs boson in association with an electroweak gauge boson. We consider decays of a Higgs boson including $ZZ, WW, \gamma \gamma$, and $Z \gamma$. Matrix element approach to three production and decay topologies is developed and applied in the analysis. A complete Monte Carlo simulation of the above processes at proton and $e^+e^-$ colliders is performed and verified by comparing it to an analytic calculation. Prospects for measuring various tensor couplings at existing and proposed facilities are compared.

Overview of Anomalous $HVV$ Interactions

The paper "Constraining anomalous $HVV$ interactions at proton and lepton colliders" explores the potential to measure anomalous couplings of the Higgs boson with vector bosons, symbolized as $H \to VV$, where $V$ includes electroweak gauge bosons ($Z$, $W$) and photons ($\gamma$), in addition to gluons ($g$). This research utilizes data-driven simulations to investigate these interactions at both the Large Hadron Collider (LHC) and projected electron-positron ($e^+e^-$) colliders, reinforcing theoretical models through experimental perspectives.

The researchers employ a differentiated approach by analyzing Higgs boson production and decay channels, particularly focusing on instances where the Higgs boson partners with $Z$, $W$, or two additional jets in production, followed by its decay into $ZZ$, $WW$, $\gamma\gamma$, and $Z\gamma$. A matrix-element method enhances the analysis, providing a coherent framework for probing these interaction characteristics.

Matrix Element Approach and Simulation

A major strength of this work is the development of a matrix element approach to ascertain the tensorial structure of the Higgs boson interactions in different production and decay topologies. Utilizing the JHUGen Monte Carlo generator, they simulate the processes with a focus on ensuring data fidelity through extensive numerical validation against analytic calculations. This is notable for its computational rigor and ensures precision fitting of data to models. These simulations not only represent current datasets but also project future collider capabilities.

Results and Observations

The simulations demonstrate that experimental settings at both the LHC and at future $e^+e^-$ facilities have the potential to offer precise determinations of anomalous couplings. Importantly, such measurements can distinguish between different possible Lorentz structures of the $HVV$ vertex, highlighting potential $C\!P$ violation elements and exploring various scenarios, such as scalar, pseudoscalar, and mixed-parity hypotheses.

Significant numerical results have been obtained, such as specific cross section ratios that reveal sensitivity thresholds for detecting $C\!P$-odd contributions in the interaction. These results illustrate the power of combining collider data with advanced simulation techniques to push the boundaries of our understanding of the Higgs boson's properties.

Implications and Future Directions

Practically, the implications of measuring these anomalous couplings are profound. They offer insights into physics beyond the Standard Model, potentially uncovering aspects of hidden sectors or new physics that could manifest in these subtle deviations from expected Higgs behavior.

Theoretically, this investigation enriches the landscape of interpretive frameworks for Higgs data, providing tools and methodologies that can be applied across particle physics research endeavors. This research stakes a claim in the ongoing dialogue concerning the Higgs boson’s role within the broader context of high-energy physics.

Looking forward, these methodologies and results offer a launching pad for ensuing generations of collider experiments with heightened sensitivity to anomalies in Higgs behaviors. They suggest robust paths to explore intrinsic property measurements with greater precision, offering substantial foundational data for theoretical validations or revisions.

Thus, this paper not only sheds light on current experimental capabilities but also sketches an ambitious outlook for future collider studies, keeping at the forefront the need for coherently constraining and understanding anomalous $HVV$ interactions.