Global Analysis of the ALP Effective Theory

TL;DR

This paper conducts a comprehensive global fit of axion-like particle (ALP) effective theory using collider and flavor data, revealing how different searches constrain ALP parameters across various mass ranges and decay modes.

Contribution

It introduces a combined analysis of collider and flavor observables with RG evolution to fully explore ALP parameter space, highlighting the importance of resonance and lifetime effects.

Findings

Resonance searches in B decays improve sensitivity to sub-GeV ALPs.

ALP lifetime affects the effectiveness of prompt, displaced, and invisible decay searches.

Flavor observables significantly constrain ALP couplings when combined with collider data.

Abstract

We perform a global fit of the effective Lagrangian for axion-like particles (ALPs) to data. By combining LHC observables from top physics, dijet and di-boson production with electroweak precision observables, we resolve the full parameter space of ALPs with flavor-universal couplings. Using the renormalization group to evolve the effective ALP couplings to low energies allows us to investigate the impact of flavor observables on the global analysis. We show that resonance searches in $B\to K$ meson decays significantly enhance the sensitivity to ALPs with sub-GeV masses. The lifetime of the ALP plays a crucial role in resolving the multi-dimensional parameter space with searches for prompt, displaced and invisible ALP decays. Our analysis points out the differences in probing an effective theory with new light particles, compared to scenarios with only non-resonant effects of heavy particles at low energies, as in the Standard Model Effective Field Theory.