发表机构
Universitat Autònoma de Barcelona; Institut de Física d’Altes Energies (IFAE); The Barcelona Institute of Science and Technology (BIST)（巴塞罗那自治大学; 高能物理研究所（IFAE）; 巴塞罗那科学技术学院（BIST））
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在手征微扰理论中推导了任意质量轴子类粒子与介子的混合及散射振幅，恢复了QCD轴子极限，并给出了包含同位旋破缺的通用参数化框架。
AI 中文摘要
我们在手征微扰理论（$\chi$PT）框架内研究一般轴子类粒子（ALP）与轻赝标量介子之间的混合，及其对低能散射和衰变过程的影响。从最一般的ALP有效拉格朗日量出发，我们推导了在ALP衰变常数和同位旋破缺的首阶下，任意ALP质量所诱导的ALP-介子动能和质量的混合。由此，我们得到物理ALP质量至$\mathcal{O}(F^2/f_a^2)$阶，恢复了QCD轴子极限，并发现任何具有零裸质量的ALP都共享QCD轴子的质量。我们提供了涉及赝标量介子和任意数量ALP的每个四体振幅的紧凑参数化。作为示例，我们展示了$K\bar{K}\to P^0a$散射。该框架适用于一般的ALP质量和耦合，并一致地纳入同位旋破缺，这对于其他情况下被禁止的过程至关重要。
英文摘要
We study the mixing between a generic axion-like particle (ALP) and the light pseudoscalar mesons within chiral perturbation theory ($χ$PT), and its consequences for low-energy scattering and decay processes. Starting from the most general ALP effective Lagrangian, we derive the ALP-meson kinetic and mass mixing induced at leading order in the ALP decay constant and isospin breaking for arbitrary ALP masses. As a result, we obtain the physical ALP mass to $\mathcal{O}(F^2/f_a^2)$, recovering the QCD-axion limit and finding that any ALP with a vanishing bare mass shares the QCD-axion mass. We provide a compact parameterization of every four-body amplitude involving pseudoscalar mesons and an arbitrary number of ALPs. As an illustration, we show the $K\bar{K}\to P^0a$ scattering. The framework applies for general ALP masses and couplings and consistently incorporates isospin breaking, essential for otherwise forbidden processes.
Comments5 pages. Proceedings of MESON2026
