Effects of the instantons and quark degrees of freedom on properties of hypernuclei

我们利用夸克集团模型研究了夸克自由度对超核的影响，夸克集团模型将瞬子诱导的相互作用和/或π-和σ交换以及传统的单胶子交换势作为两夸克相互作用。从夸克集团模型出发，构造了一个重现已知散射观测的现实的双重子势。这种QCM势具有由夸克相互作用引起的短程斥力和来自重子间单玻色子交换的中程和长程引力。QCM势是非定域的，因为原始模型具有重子的内部自由度，所以它与能量无关，可用于研究超核。我们已经评估了它的非定域性的影响。利用逆散射方法，构造了与原QCM势具有相同壳面值的等效局域势。比较了原始势场和等价局域势场的G-矩阵，以考察它们的脱壳性质。在夸克-泡利阻塞效应较小的通道中，发现两个势的G矩阵相似；等效的局域势似乎模拟了QCM势。另一方面，在夸克-泡利阻塞禁止大部分Os组态的通道中，由等效非局域势得到的G-矩阵在k&gt；1.5fm^&lt；-1&gt；处与原始G-矩阵有很大的不同。此外，当组态中包含重子中夸克的关联时，手征夸克模型重现了正、负激发重子的正确质量有序。我们还发现，假设u-夸克和d-夸克之间的质量差与当前夸克的质量差相同，可以定量地解释核力电荷对称性破缺的短程部分。

We have investigated the effects of quark degrees of freedom on hypernuclei by employing the quark cluster model (QCM) with the instanton-induced interaction and/or π-and σ-exchange as well as the conventional one-gluon-exchange potential as two-quark interactions.A realistic two-baryon potential which reproduces the known scattering observables was constructed from QCM. This QCM potential has a short range repulsion arising from the quark interaction and the middle and a long-range attraction coming from the one-boson exchange between the baryons. It is energy-independent and can be employed to investigate hypernuclei.The QCM potential is nonlocal, because the original model has the internal degrees of freedom of baryons. We have evaluated the effects of its nonlocality. By using the inverse scattering method, the equivalent local potential which gives the same on-shell values as those of the original QCM potential was constructed. The G-matrices of the original and of the equivalent local potentials were compared to each other to investigate their off-shell properties. In the channels where the quark-Pauli-blocking effects are small, the G-matrices of the two potentials were found to be similar to each other; the equivalent local potential seems to simulate the QCM potential. On the other hand, in the channels where the quark-Pauli-blocking forbids most of the Os configuration, the G-matrix obtained from the equivalent nonlocal potential differs significantly from the original one at k>1.5fm^<-1>.Moreover, when the correlation of quarks in the baryon is included in the configuration, the chiral quark model was found to reproduce the correct mass ordering of the positive and negative excited baryons. It was also found that suppose the mass difference between u-and d-constituent quarks is the same as that of current quarks, the short-range part of the charge symmetry breaking of the nuclear force can be explained quantitatively.