VBFNLO: A parton level Monte Carlo for processes with electroweak bosons

Abstract: VBFNLO is a fully flexible parton level Monte Carlo program for the simulation of vector boson fusion, double and triple vector boson production in hadronic collisions at next-to-leading order in the strong coupling constant. VBFNLO includes Higgs and vector boson decays with full spin correlations and all off-shell effects. In addition, VBFNLO implements CP-even and CP-odd Higgs boson via gluon fusion, associated with two jets, at the leading-order one-loop level with the full top- and bottom-quark mass dependence in a generic two-Higgs-doublet model. A variety of effects arising from beyond the Standard Model physics are implemented for selected processes. This includes anomalous couplings of Higgs and vector bosons and a Warped Higgsless extra dimension model. The program offers the possibility to generate Les Houches Accord event files for all processes available at leading order.

• The paper presents a Monte Carlo framework that computes high-order electroweak boson production and decay processes with precision.
• It offers extensive cross-section calculations and explores anomalous gauge couplings, providing benchmarks for experimental validations.
• It investigates CP violation effects and stable differential distributions, enhancing predictions for Higgs production and vector boson fusion.

Analysis of Complex Particle Processes in High-Energy Physics

This paper provides a detailed exploration into particle interactions and processes in high-energy physics, with a particular focus on the various mechanisms of vector boson production and Higgs boson decay. Utilizing a comprehensive array of Feynman diagrams and calculations, the authors delve deeply into the interactions involving W and Z bosons, as well as other related vector gauge bosons, exploring channels like WW, ZZ, and WZ heavily.

Overview of Particle Processes

The emphasis in this paper is predominantly on parton-parton (pp) collisions that result in boson production, interactions, and decays. The processes examined include a wide array of final states, including multi-lepton, multi-jet, and photon interactions. The calculations extend to higher-order corrections in the electroweak sector and high precision measurements, capturing detailed characteristics of each interaction.

1. Higgs Boson Processes: The authors investigate Higgs production in association with jets (Hjj and Hjjj), exploring multiple decay channels such as $H \to \gamma\gamma$, $H \to \tau\tau$, and $H \to bb$. Special focus is given to vector boson fusion and the role of electroweak corrections in accurately predicting cross-sections and branching ratios.
2. Cross-Section Calculations: Extensive numerical results for cross-sections are demonstrated, showcasing the perturbative reliability and utility of these high-order calculations. Results are given for both inclusive and exclusive cross-sections, serving as benchmarks for comparison with experimental data gathered from collider experiments such as those conducted at CERN.
3. CP Violation: There is a comprehensive study on CP-violating effects in these processes. Theoretical constructs such as the effective Lagrangian at dimension-5 operators are examined, providing insights into potential sources and manifestations of CP violation in vector boson interactions.

Key Findings

• Higher-Order Correction Efficacies: The paper reports on significant corrections and their implications in refining bosonic interaction predictions. These findings cement the importance of next-to-leading order (NLO) computations in achieving precise agreement with experimental data.
• Anomalous Couplings: Probing into anomalous triple and quartic gauge couplings presents intriguing assertions that could signify physics beyond the Standard Model. The constraints and predicted deviations from expected outcomes have potential implications for new theories and models.
• Numerical Stability and Precision: The authors achieve considerable stability in the calculation of differential distributions and total cross sections, reflecting robust computational methodologies.

Implications and Future Directions

The comprehensive study on diverse high-energy processes involving bosons not only improves the understanding of fundamental interactions but also aids in the calibration of particle detectors and the refinement of theoretical models. Future research could focus on exploring the consequences of these refined calculations on potential new physics signatures. The role of machine learning and automated computation techniques in handling such complex calculations is also a burgeoning field that promises to yield efficiency gains and uncover intricate particle interactions at higher dimensions.

In conclusion, this paper expands the toolkit available to physicists aiming to unravel and sequence the myriad of complex processes driving particle collisions and interactions. As high energy physics experiments evolve, these methodologies will be crucial to interpret data and probe the boundaries of the known universe.