One-loop corrections to ALP couplings

TL;DR

This paper calculates the one-loop quantum corrections to axion-like particle (ALP) couplings with Standard Model particles, considering off-shell effects and finite corrections, with implications for collider and astrophysical searches.

Contribution

It provides the complete one-loop effective couplings of ALPs to SM particles, including off-shell effects and finite corrections, in a covariant gauge, which was not previously available.

Findings

Derived the one-loop ALP-SM effective couplings including finite corrections.

Analyzed phenomenological implications for collider and astrophysical ALP searches.

Provided constraints on ALP-top quark coupling from LHC and dark matter experiments.

Abstract

We derive the one-loop contributions to ALP-SM effective couplings, including all finite corrections. The complete leading-order -- dimension five -- effective linear Lagrangian is considered. The ALP is left off-shell, which is of particular impact on LHC and accelerator searches of ALP couplings to $\gamma\gamma$, $ZZ$, $Z\gamma$, $WW$, gluons and fermions. All results are obtained in the covariant $R_\xi$ gauge. A few phenomenological consequences are also explored as illustration, with flavour diagonal channels in the case of fermions: in particular, we explore constraints on the coupling of the ALP to top quarks, that can be extracted from LHC data, from astrophysical sources and from Dark Matter direct detection experiments such as PandaX, LUX and XENON1T.