Exploring interference effects between two ALP effective operators at the LHC

TL;DR

This paper investigates the combined effects of multiple ALP effective operators at the LHC, demonstrating how interference can be used to better constrain ALP interactions with standard model particles.

Contribution

It introduces a novel approach that considers multiple ALP operators simultaneously, revealing interference effects and improving constraints on ALP interactions at the LHC.

Findings

Future bounds on the ALP decay constant can reach around 10-20 TeV.

Interference effects enable combined constraints on ALP interactions.

The approach applies to specific production channels with promising sensitivity.

Abstract

We observe that most studies of axion-like particle (ALP) production channels at the Large Hadron Collider (LHC) focus on a single type of ALP operator for each process in the effective field theory framework. In this work, we propose an alternative approach that considers two or more types of relevant ALP effective operators together in some specific ALP production channels and study their interference effects. Using the $p p\rightarrow t j a$ process with $a\rightarrow\gamma\gamma$ as an example, we show that this approach allows us to constrain the ALP interactions with both the $W$ boson and the top quark, as well as their interference in a single process. For the final state with two isolated photons and a top quark decaying semi-leptonically, we predict that the future bounds on the ALP decay constant can reach around $f_a \sim 10\;(20) $ TeV for $25$ GeV $< M_a < 100$ GeV at the LHC with 300 (3000) fb$^{1}$ luminosity.