Precise tests of the axion coupling to tops

TL;DR

This paper investigates the coupling of axion-like particles to top quarks at the LHC by calculating top-antitop production rates including ALP effects, providing constraints on their interactions for models with dominant top couplings.

Contribution

It offers the first detailed one-loop level analysis of ALP effects on top-pair production, constraining top couplings for ALPs below the top-antitop threshold.

Findings

Constraints on ALP-top couplings derived from LHC data

ALP effects significantly modify top-pair production distributions

Results applicable to UV completions with dominant top couplings

Abstract

We present an in-depth analysis of axions and axion-like particles in top-pair production at the LHC. Our main goal is to probe the axion coupling to top quarks at high energies. To this end, we calculate the top-antitop cross section and differential distributions including ALP effects up to one-loop level. By comparing these predictions with LHC precision measurements, we constrain the top coupling of axion-like particles with masses below the top-antitop threshold. Our results apply to all UV completions of the ALP effective theory with dominant couplings to top quarks, in particular to DFSZ-like axion models.