AutoEFT: Constructing and exploring on-shell bases of effective field theories

Abstract: Effective Field Theories (EFTs) provide a framework for capturing the effects of yet unseen heavy degrees of freedom in a model-independent manner. However, constructing a complete and minimal set of operators, especially at higher mass dimensions, is challenging. We present AutoEFT, an implementation of an algorithm that systematically handles redundancies among operators due to equations of motion, integration-by-parts identities, Fierz identities, and repeated fields. This algorithm enables the construction of on-shell bases for a broad range of EFTs. Additionally, it facilitates the exploration of various aspects within this field, such as investigating higher mass dimensions or the relationship between different operator bases. AutoEFT can be applied to phenomenologically relevant theories like the Standard Model and its extensions, including new light particles or additional symmetry groups.