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arXiv 2312.16675hep-phhep-lat
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扩展NJL模型中磁化赝标介子和矢量介子的质量:轴矢量介子的作用

Masses of magnetized pseudoscalar and vector mesons in an extended NJL model: the role of axial vector mesons

Máximo Coppola, Daniel Gomez Dumm, Santiago Noguera, Norberto N. Scoccola

AI总结:

本研究在扩展NJL模型中考虑轴矢量介子混合,计算磁化赝标和矢量介子质量谱,发现该混合改善与LQCD的定性一致,并影响介子凝聚条件。

摘要:

我们研究了在外部均匀磁场 $\vec B$ 存在下,轻赝标介子和矢量介子的质量谱,并考虑了与轴矢量介子扇区混合的效应。该分析在包含同位旋标量和同位旋矢量耦合以及风味混合的't Hooft-like项的双味NJL类模型中进行。磁场对带电粒子的影响通过保留夸克传播子所携带的Schwinger相位,并在适当的Ritus-like基中展开相应的介子场来考虑。还分析了介子质量态的自旋-同位旋和自旋-风味分解。对于中性π介子质量,研究表明与轴矢量介子的混合改善了先前的理论结果,导致其随$B$单调递减的行为,与LQCD计算在定性上良好一致,无论是常数耦合还是$B$依赖耦合的情况。对于带电π介子,可以看到混合减弱了其质量随$B$的增强。因此,能量变得低于点状π介子对应的能量,改善了与LQCD结果的一致性。对于最低的$ρ^+$能量态的磁性行为,一致性也得到了改善,该能量态在所考虑的$B$值范围内不为零——这一事实可能与强磁场下介子凝聚的发生有关。

英文摘要:

We study the mass spectrum of light pseudoscalar and vector mesons in the presence of an external uniform magnetic field $\vec B$, considering the effects of the mixing with the axial vector meson sector. The analysis is performed within a two-flavor NJL-like model which includes isoscalar and isovector couplings together with a flavor mixing 't Hooft-like term. The effect of the magnetic field on charged particles is taken into account by retaining the Schwinger phases carried by quark propagators, and expanding the corresponding meson fields in proper Ritus-like bases. The spin-isospin and spin-flavor decomposition of meson mass states is also analyzed. For neutral pion masses it is shown that the mixing with axial vector mesons improves previous theoretical results, leading to a monotonic decreasing behavior with $B$ that is in good qualitative agreement with LQCD calculations, both for the case of constant or $B$-dependent couplings. Regarding charged pions, it is seen that the mixing softens the enhancement of their mass with $B$. As a consequence, the energy becomes lower than the one corresponding to a pointlike pion, improving the agreement with LQCD results. The agreement is also improved for the magnetic behavior of the lowest $ρ^+$ energy state, which does not vanish for the considered range of values of $B$ -- a fact that can be relevant in connection with the occurrence of meson condensation for strong magnetic fields.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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