The SMEFTsim package, theory and tools (1709.06492v2)

Abstract: We report codes for the Standard Model Effective Field Theory (SMEFT) in FeynRules -- the SMEFTsim package. The codes enable theoretical predictions for dimension six operator corrections to the Standard Model using numerical tools, where predictions can be made based on either the electroweak input parameter set ${\hat{\alpha}{ew}, \hat{m}_Z, \hat{G}_F }$ or ${\hat{m}{W}, \hat{m}_Z, \hat{G}_F}$. All of the baryon and lepton number conserving operators present in the SMEFT dimension six Lagrangian, defined in the Warsaw basis, are included. A flavour symmetric ${\rm U}(3)^5$ version with possible non-SM $\rm CP$ violating phases, a (linear) minimal flavour violating version neglecting such phases, and the fully general flavour case are each implemented. The SMEFTsim package allows global constraints to be determined on the full Wilson coefficient space of the SMEFT. As the number of parameters present is large, it is important to develop global analyses on reduced sets of parameters minimizing any UV assumptions and relying on IR kinematics of scattering events and symmetries. We simultaneously develop the theoretical framework of a "W-Higgs-Z pole parameter" physics program that can be pursued at the LHC using this approach and the SMEFTsim package. We illustrate this methodology with several numerical examples interfacing SMEFTsim with MadGraph5. The SMEFTsim package can be downloaded at https://feynrules.irmp.ucl.ac.be/wiki/SMEFT

• The paper presents the SMEFTsim package as a comprehensive toolkit for analyzing all baryon and lepton number conserving dimension-six SMEFT operators.
• It details flexible flavor symmetries and versatile electroweak input schemes to support diverse theoretical and phenomenological studies.
• The package integrates with MadGraph5, enabling advanced collider simulations and global constraints on Wilson coefficients for probing new physics.

Overview of the SMEFTsim Package

The paper "The SMEFTsim package, theory and tools" by Ilaria Brivio, Yun Jiang, and Michael Trott presents a comprehensive toolkit for analyzing the Standard Model Effective Field Theory (SMEFT) using the SMEFTsim package. This toolkit is essential for researchers focusing on beyond the Standard Model physics, enabling them to incorporate constraints and predictions for dimension-six operators ubiquitously in experimental data.

Key Contributions

The SMEFTsim package offers several vital features:

1. Comprehensive Implementation: The package includes all baryon and lepton number conserving operators present in the SMEFT dimension-six Lagrangian, delineated in the Warsaw basis. This ensures a complete framework for theoretical and phenomenological studies.
2. Flexibility in Flavour Symmetries: It supports multiple symmetry assumptions, including the fully general flavour case, a flavour symmetric ${\rm U}(3)^5$ version, and a Minimal Flavour Violating (MFV) version, each allowing different CP-violating phases.
3. Input Parameter Versatility: Researchers can perform analysis using various Electroweak input parameter schemes, such as $\{\hat{\alpha}_{ew}, \hat{m}_Z, \hat{G}_F \}$ or $\{\hat{m}_{W}, \hat{m}_Z, \hat{G}_F \}$, allowing for flexibility in theoretical input assumptions.
4. Integration with MadGraph5: The package is designed to interface seamlessly with MadGraph5, enabling the generation of events and cross-sections using EFT methods. This feature facilitates detailed collider simulations that incorporate SMEFT corrections.

Strong Numerical Results and Implications

The paper emphasizes the importance of global analyses and the development of analyses with reduced parameter sets to minimize UV assumptions while relying on IR kinematics. One substantial outcome of using SMEFTsim is the ability to determine global constraints across the full Wilson coefficient space, thus empowering researchers to systematically probe the parameter space of beyond the Standard Model physics.

Moreover, the introduction of a "W-Higgs-Z pole parameter" physics program illustrates a methodology for global analysis. This theoretical framework is particularly relevant at the LHC, where scattering events and symmetries can be exploited in a collider environment to enhance sensitivity to new physics. The numerical examples interfacing SMEFTsim with MadGraph5 underscore the potential of these methods in practical applications.

Speculations and Future Developments

The SMEFTsim package sets the stage for advanced theoretical and experimental harmonization in high-energy physics. Future developments in AI and computational power could dramatically accelerate these analyses, allowing for real-time data interpretation and feedback loops between theory and experiment. Moreover, as experimental measurements become more precise, there will be increasing demand for next-to-leading-order (NLO) implementations within the SMEFT framework, a challenge that SMEFTsim could help address.

The paper serves as a benchmark for integrating effective field theory with cutting-edge computational tools, offering a pathway to examine subtle deviations from SM predictions and guiding searches for new physics at the energy frontier. Researchers adopting SMEFTsim will have a robust and flexible toolset to explore the rich phenomenology of the SMEFT and its implications for future particle physics discoveries.