New Opportunities for Detecting Axion-Lepton Interactions.

Area of Science:

• Particle Physics
• Beyond Standard Model Physics

Background:

• Axionlike particles (ALPs) are hypothetical particles proposed as dark matter candidates.
• Existing constraints on ALP interactions with leptons are revisited and refined.
• Subtleties in ALP parameter space require clarification for accurate theoretical predictions.

Purpose of the Study:

• To re-examine the theoretical framework and experimental constraints for axionlike particles (ALPs) interacting with leptons.
• To identify novel avenues for ALP detection by analyzing their interactions.
• To differentiate between weak-violating and weak-preserving ALPs and their distinct phenomenological consequences.

Main Methods:

• Theoretical analysis of ALP interactions with leptons.
• Investigation of "energy enhancement" effects in particle decay processes.
• Re-evaluation of existing experimental constraints and proposal of new search strategies.

Main Results:

• A qualitative distinction between weak-violating and weak-preserving ALPs is established.
• New constraints on ALP parameter space are derived, impacting both types of ALPs.
• Enhanced detection opportunities are identified in charged meson decays (e.g., π⁺→e⁺νa, K⁺→e⁺νa) and W boson decays.

Conclusions:

• The findings refine our understanding of ALP physics and their interactions with Standard Model particles.
• New experimental searches for ALPs can be designed based on the identified decay channels.
• This work has implications for the QCD axion and the explanation of experimental anomalies using ALPs.