Probe of axion-like particles in vector boson scattering at a muon collider

TL;DR

This paper investigates the potential to detect axion-like particles through diphoton production at future muon colliders with energies up to 100 TeV, deriving bounds much stronger than current limits.

Contribution

It provides a detailed analysis of ALP couplings to gauge bosons at muon colliders and establishes new exclusion regions and unitarity constraints for ALP detection.

Findings

Stronger bounds on ALP-gauge boson couplings than current experiments.

Unitarity constraints are satisfied in the studied coupling region.

Differential cross sections and exclusion regions are derived for various collider energies.

Abstract

We have examined the sensitivity to the axion-like particle (ALP) couplings to electroweak gauge bosons in the diphoton production at a future muon collider. The collisions at the $\mu^+ \mu^-$ energies of 3 TeV, 14 TeV, and 100 TeV are addressed. The differential cross sections versus the invariant mass of the final photons and total cross section versus minimal diphoton invariant mass are presented. We have derived the exclusion regions for the ALP-gauge boson coupling. The obtained bounds are much stronger than the current experimental bounds in the ALP mass region 10 GeV -- 10 TeV. The partial-wave unitarity constraints on the ALP-gauge boson coupling are estimated. We have shown that the unitarity is not violated in the region of the ALP coupling studied in the present paper.