从阈值跨越到波函数重整化：定义磁场中的π介子莫特温度
From Threshold Crossing to Wave-function Renormalization: Defining the Pion Mott Temperature in a Magnetic Field
- Universidade Federal de Santa Catarina（圣卡塔琳娜联邦大学）
- CNEA, Departamento de Física Teórica (DFTIFSC)（阿根廷国家原子能委员会理论物理系）
- Universidade Federal de Santa Maria（圣玛丽亚联邦大学）
- CONICET（阿根廷国家科学研究委员会）
- CFisUC, Department of Physics, University of Coimbra（科英布拉大学物理中心）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
研究热磁化夸克物质中中性π介子的解离，提出以π介子波函数重整化因子的拐点定义磁场中的莫特温度，该方案可重现零磁场结果并追踪手征赝临界温度，表明π介子解离为谱交叉过程。
AI中文摘要：
我们在两味道Nambu–Jona-Lasinio模型框架下，研究热磁化夸克物质中中性π介子的解离行为。在零磁场条件下，莫特温度通常由$m_{\pi^0}(T_{\rm Mott})=2M(T_{\rm Mott})$确定，高于该温度时不再存在实极点。在有限磁场下，朗道量子化将这单一阈值替换为一系列夸克-反夸克连续谱，并产生π介子极点方程的多个解，使得直接的阈值跨越判据变得模糊，因为在最低名义阈值以下始终存在实π介子解。因此，我们提出通过最低极点对应的π介子波函数重整化因子$Z_{\pi^0}(T,eB)$的拐点来定义磁场中的莫特温度，该拐点对应其谱函数强度的最快损失。该方案在$eB\to0$时可重现传统莫特温度，且对于常数及依赖磁场的耦合均能追踪手征赝临界温度。我们的结果表明，磁场中π介子的解离是一种谱交叉而非简单的阈值跨越。
英文摘要：
We investigate the dissociation of the neutral pion in hot magnetized quark matter within the two-flavor Nambu--Jona-Lasinio model. At zero magnetic field, the Mott temperature is conventionally determined by $m_{π^0}(T_{\rm Mott})=2M(T_{\rm Mott})$, above which a real pole ceases to exist. At finite magnetic field, Landau quantization replaces this single threshold by a hierarchy of quark--antiquark continua and generates multiple solutions of the pion pole equation, rendering a direct threshold-crossing criterion ambiguous since a real pion solution below the lowest nominal threshold always exists. We therefore propose to define the magnetic Mott temperature through the inflection point of the pion wave-function renormalization factor $Z_{π^0}(T,eB)$ of that lowest pole, corresponding to the fastest loss of its spectral function strength. The prescription reproduces the conventional Mott temperature as $eB\to 0$ and tracks the chiral pseudocritical temperature for both constant and magnetic-field-dependent couplings. Our results characterize pion dissociation in a magnetic field as a spectral crossover rather than a simple threshold crossing.
