[Paper Review] Effective field theory for top quark physics

Cen Zhang, S. Willenbrock|arXiv (Cornell University)|Jan 1, 2010

Particle physics theoretical and experimental studies7 citations

TL;DR

This paper advocates for the effective field theory (EFT) approach as a superior framework for modeling physics beyond the Standard Model that indirectly affects top quark interactions. By systematically organizing higher-dimensional operators, EFT provides a more fundamental, consistent, and computationally simpler description than the traditional vertex-function method, offering clearer theoretical interpretation and predictive power in top quark phenomenology.

ABSTRACT

Physics beyond the standard model can affect top-quark physics indirectly. We describe the effective field theory approach to describing such physics, and contrast it with the vertex-function approach that has been pursued previously. We argue that the effective field theory approach has many fundamental advantages and is also simpler.

Motivation & Objective

• To provide a systematic framework for describing physics beyond the Standard Model that indirectly influences top quark processes.
• To address the limitations of the vertex-function approach, which lacks theoretical consistency and clarity in operator structure.
• To establish effective field theory as a more fundamental and practical tool for top quark phenomenology.
• To simplify the description of new physics effects in top quark couplings and decay processes.

Proposed method

• Employing the framework of effective field theory to systematically include higher-dimensional operators suppressed by a new physics scale.
• Identifying and classifying dimension-6 operators that modify top quark couplings to gauge bosons and the Higgs boson.
• Using the Wilson coefficient formalism to parameterize deviations from the Standard Model in a model-independent way.
• Applying the EFT approach to compute corrections to top quark production and decay rates, including loop-level effects.
• Comparing the EFT results with those from the vertex-function method to highlight theoretical and computational advantages.
• Ensuring gauge invariance and renormalizability by construction through the EFT formalism.

Experimental results

Research questions

• RQ1 How can physics beyond the Standard Model be systematically described when it affects top quark processes indirectly?
• RQ2 What are the theoretical and computational advantages of effective field theory over the vertex-function approach in top quark physics?
• RQ3 How does the EFT framework ensure consistency and renormalizability in describing new physics effects?
• RQ4 In what ways does EFT simplify the analysis of top quark couplings and decay processes compared to previous methods?
• RQ5 Can EFT provide a clearer interpretation of experimental data on top quark properties?

Key findings

• The effective field theory approach provides a more fundamental and consistent description of new physics effects in top quark processes compared to the vertex-function method.
• EFT systematically organizes higher-dimensional operators, leading to a clearer theoretical interpretation of deviations from the Standard Model.
• The method ensures gauge invariance and renormalizability by construction, avoiding ambiguities present in the vertex-function approach.
• The EFT framework simplifies calculations of top quark production and decay rates by reducing the number of independent parameters and symmetries.
• The approach allows for a model-independent analysis of top quark couplings, enabling broader applicability across different BSM scenarios.
• EFT enables a more transparent connection between experimental measurements and underlying new physics scales.