A comprehensive approach to new physics simulations (0906.2474v1)

Abstract: We describe a framework to develop, implement and validate any perturbative Lagrangian-based particle physics model for further theoretical, phenomenological and experimental studies. The starting point is FeynRules, a Mathematica package that allows to generate Feynman rules for any Lagrangian and then, through dedicated interfaces, automatically pass the corresponding relevant information to any supported Monte Carlo event generator. We prove the power, robustness and flexibility of this approach by presenting a few examples of new physics models (the Hidden Abelian Higgs Model, the general Two-Higgs-Doublet Model, the most general Minimal Supersymmetric Standard Model, the Minimal Higgsless Model, Universal and Large Extra Dimensions, and QCD-inspired effective Lagrangians) and their implementation/validation in FeynArts/FormCalc, CalcHep, MadGraph/MadEvent, and Sherpa.

Overview of "A Comprehensive Approach to New Physics Simulations"

The paper introduces a sophisticated framework designed to assist researchers in developing, implementing, and validating new particle physics models based on perturbative Lagrangians. It aims to facilitate the exploration of Beyond the Standard Model (BSM) physics, which is crucial given the complex data expected from the Large Hadron Collider (LHC). The research highlights the integration of theory with experimental setups through automated computational tools.

Key Framework Components

1. FeynRules Package: At the core of this framework is the FeynRules package, a robust tool that allows physicists to derive Feynman rules from a given Lagrangian directly. By leveraging software such as Mathematica, FeynRules automates the generation of interaction vertices and parameter definitions, simplifying the implementation of complex models.
2. Comprehensive Interfaces: The framework includes various interfaces for Monte Carlo (MC) event generators such as MadGraph, CalcHEP, Sherpa, and FeynArts. These interfaces translate models into the respective formats required by each tool, allowing for seamless integration across different computational environments.
3. Validation and Verification: It emphasizes rigorous testing and comparison against existing models and experimental data. This includes comparison of cross-section results and decay widths across different software tools to ensure consistency and accuracy.

Models Implemented

Several BSM scenarios are addressed, including:

• Two-Higgs-Doublet Model (2HDM): Extending the scalar sector of the Standard Model to include additional Higgs doublets, providing a framework for studying CP violation and flavor-changing neutral currents.
• Minimal Supersymmetric Standard Model (MSSM): A detailed implementation capable of handling complex mixing in the scalar sector and incorporating R-parity conserving processes.
• Minimal Higgsless Model: Focuses on models where electroweak symmetry breaking occurs without a fundamental Higgs field, providing alternatives to the Higgs mechanism.
• Extra Dimensional Models: Covers Universal Extra Dimensions (UED) and Large Extra Dimensions (LED) by naturally embedding the extra fields and explaining observed phenomena at higher energies.

Implications and Future Directions

The framework presented offers a significant step towards unifying theoretical and experimental physics through computational tools. By automating the derivation of Feynman rules and facilitating the implementation in multiple simulation environments, it allows for rapid prototyping and testing of new theories. This is particularly relevant in the context of the LHC, where rapid feedback between theoretical developments and experimental findings is crucial.

The paper speculates on the future expansion of the framework to include more processes and loop-level calculations. The potential for automating next-to-leading order computations in BSM processes is particularly promising, indicating a future where complex theoretical models can be implemented and tested without the time-consuming manual intervention often required today.

In conclusion, the framework significantly decreases the barrier to entry for testing new physics models, allowing researchers to quickly adapt and test theories against experimental data. This enhancement in the simulation capacity and validation ensures a more robust pipeline for exploring the unknown landscapes of particle physics.