Comprehensive Effective Field Theory Analysis for Baryon Number Violating Processes

TL;DR

This paper develops a comprehensive, model-independent EFT framework connecting high-energy baryon number violation to low-energy observables, enabling better interpretation of experimental searches for baryon number violation.

Contribution

It introduces a systematic pipeline analysis linking SMEFT and LEFT operators up to dimension nine and eight, respectively, with chiral perturbation theory, expanding the scope of UV completions considered.

Findings

Complete set of dimension-eight LEFT operators includes all chiral representations.

Higher-dimensional operators allow for a broader class of UV models.

Matching from higher-order SMEFT operators incorporates more UV scenarios.

Abstract

Baryon number-violating processes arise generically in many extensions of the Standard Model, with Grand Unified Theories providing the most compelling realizations. Ongoing experimental searches at JUNO, Hyper-K, and DUNE motivate a more precise and model-independent analysis utilizing the effective field theory (EFT) framework capable of connecting ultraviolet dynamics to low-energy hadronic observables. In this work, we perform a pipeline analysis that connects baryon number-violating (BNV) new physics to its low-energy description through the Standard Model EFT (SMEFT) up to dimension nine and the Low-Energy EFT (LEFT) up to dimension eight, and subsequently matches onto chiral perturbation theory using a systematic spurion method. We show that the complete set of dimension-eight LEFT operators enables the inclusion of the full set of chiral representations for three-quark operators with derivatives, which are also embedded in the chiral Lagrangian after quark-hadron matching. By contrast, the conventional dimension-six operators generate only the $(\bar{\mathbf{3}},\mathbf{3})$ and $(\mathbf{8},\mathbf{1})$ representations. The higher dimensional LEFT operators should be matched from higher order SMEFT operators, and thus a wider class of UV completions are allowed. We consider the complete tree-level UV resonances for dimension 6 and 7 SMEFT operators, and representative UVs for higher dimension operators.