WCxf: an exchange format for Wilson coefficients beyond the Standard Model

TL;DR

This paper introduces WCxf, a standardized data exchange format for Wilson coefficients in beyond Standard Model physics, enabling seamless interfacing of various computational tools and models.

Contribution

It defines a comprehensive, extensible, and industry-standard format for Wilson coefficients, with implementations for SMEFT and WET, and provides tools for manipulation and translation.

Findings

Implemented WCxf for SMEFT and WET

Added interfaces to public EFT codes

Provided utilities for basis translation and matching

Abstract

We define a data exchange format for numerical values of Wilson coefficients of local operators parameterising low-energy effects of physics beyond the Standard Model. The format facilitates interfacing model-specific Wilson coefficient calculators, renormalisation group (RG) runners, and observable calculators. It is designed to be unambiguous (defining a non-redundant set of operators with fixed normalisation in each basis), extensible (allowing the addition of new EFTs or bases by the user), and robust (being based on industry standard file formats with parsers implemented in many programming languages). We have implemented the format for the Standard Model EFT (SMEFT) and for the weak effective theory (WET) below the electroweak scale and have added interfaces to a number of public codes dealing with SMEFT or WET. We also provide command-line utilities and a Python module for convenient manipulation of WCxf files, including translation between different bases and matching from SMEFT to WET.