ALP-SMEFT Interference

TL;DR

This paper investigates how light axion-like particles (ALPs) influence SMEFT Wilson coefficients through renormalization-group evolution, affecting observables like the top quark magnetic dipole moment and electroweak precision tests.

Contribution

It provides the first calculation of ALP-induced contributions to SMEFT operators via one-loop renormalization, highlighting their impact beyond heavy new particles.

Findings

ALPs induce non-zero SMEFT Wilson coefficients through RG evolution.

ALP interactions can significantly affect top quark magnetic dipole moments.

Electroweak precision constraints limit ALP couplings.

Abstract

The Standard Model Effective Field Theory (SMEFT) offers a powerful theoretical framework for parameterizing the low-energy effects of heavy new particles with masses far above the scale of electroweak symmetry breaking. Additional light degrees of freedom extend the effective theory. We show that light new particles that are weakly coupled to the SM via non-renormalizable interactions induce non-zero Wilson coefficients in the SMEFT Lagrangian via renormalization-group evolution. For the well-motivated example of axions and axion-like particles (ALPs) interacting with the SM via classically shift-invariant dimension-5 interactions, we calculate how these interactions contribute to the one-loop renormalization of the dimension-6 SMEFT operators, and how this running sources additional contributions to the Wilson coefficients on top of those expected from heavy new states. As an application, we study the ALP contributions to the magnetic dipole moment of the top quark and comment on implications of electroweak precision constraints on ALP couplings.