论文标题
基于现象模型
Spectral function of the $η'$ meson in nuclear medium based on phenomenological models
论文作者
论文摘要
通过有或没有空间动量的$η'$ Meson的光谱函数的中等修饰，通过使用两个现象学模型对$η'n$散射进行了$tρ$近似的研究；一个称为耦合通道模型，另一个称为$ N（1895）$ - 优势模型。在前者的模型中，$η'n$散射幅度是在涉及$η'n$通道的单位化耦合通道方法中计算的，而在后者模型中，$η'n$散射过程由$ n（1895）$ n（1895）$ j^p = 1/2/2^ - 2^ - $。在\ com {耦合通道模型}中，频谱函数中的一个$η'$模式的一个峰出现，并且峰位置转移到更高的能量，以及核密度的增加，反映了排斥的$η'n$散射长度的构造耦合耦合的耦合 - 计算机振幅。另一方面，与$η'$和$ n（1895）$ - 孔模式有关的两个分支出现在$ n（1895）$ - 优势模型中。在这两种模型中，在核介质中，在$η''$中的正常核密度下，光谱函数的峰位置和光谱函数的宽度的变化为几十MEV。一旦打开空间动量，光谱函数中的峰位置接近无核培养基效应的能量。特别是，在$ N（1895）$ - 优势模型中，随着有限动量，$ n（1895）$ - 孔模式的峰值强度会变小，而光谱功能则具有一个峰值。
The in-medium modification of the spectral function of the $η'$ meson with and without the spatial momentum is studied with the $Tρ$ approximation by employing two phenomenological models for the $η'N$ scattering; one is called coupled channels model and the other the $N(1895)$-dominance model. In the former model, the $η'N$ scattering amplitude is calculated in the unitarized coupled-channel approach involving the $η'N$ channel, while in the latter model the $η'N$ scattering process is dominated by the $N(1895)$ resonance with the spin and parity $J^P=1/2^-$. In the \com{coupled channels model}, one single peak of the in-medium $η'$ mode appears in the spectral function and the peak position shifts to higher energies along with the increase of the nuclear density reflecting the repulsive $η'N$ scattering length of the unitarized coupled-channel amplitude. On the other hand, two branches related to the $η'$ and $N(1895)$-hole modes appear in the $N(1895)$-dominance model. In both models, the shift of the peak position and the width in the spectral function are a few tens of MeV at the normal nuclear density for the $η'$ meson at rest in the nuclear medium. Once the spatial momentum is turned on, the peak positions in the spectral function approach the energies without the nuclear medium effect. Particularly, in the $N(1895)$-dominance model, the peak strength of the $N(1895)$-hole mode gets smaller with the finite momentum and the spectral function comes to have one single peak.
