High Quality QCD Axion and the LHC

Area of Science:

• Particle Physics
• Cosmology
• High Energy Physics

Background:

• The strong CP problem in Quantum Chromodynamics (QCD) is addressed by the QCD axion.
• Minimal axion models face the
• axion quality problem
• which can be resolved by introducing a mirror sector with Z_{2} symmetry.

Purpose of the Study:

• To investigate a robust realization of the QCD axion in a model with a mirror sector.
• To explore the potential of this
• heavy axion
• to be detected as a long-lived particle (LLP) at the Large Hadron Collider (LHC).

Main Methods:

• Theoretical analysis of a QCD axion model with a softly broken Z_{2} symmetry and a mirror sector.
• Investigating the production and decay signatures of the heavy axion at hadron colliders.
• Analyzing the feasibility of distinguishing axion decay signals from background processes at the LHC.

Main Results:

• The proposed heavy axion model satisfies theoretical and observational constraints.
• The heavy axion possesses a large, unexplored parameter space amenable to LHC searches.
• The unique hadronic decay signal of the axion can be identified against background noise in the long-lived particle regime.

Conclusions:

• The study establishes a new avenue for discovering axions at accelerators.
• Singly produced long-lived particles (LLPs) offer a promising search channel at the LHC.
• This research expands the scope of observable axion physics in high-energy collider experiments.