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

采用夸克集团模型（QCM），考虑了夸克与夸克之间的相互作用，并考虑了夸克与夸克之间的π-和σ-交换以及传统的单胶子交换势，研究了夸克自由度对超核的影响.这种QCM势具有由夸克相互作用产生的短程排斥和由重子之间的单玻色子交换产生的中长程吸引。由于原模型具有重子的内部自由度，因此QCM势是非定域的。我们评估了其非定域性的影响。利用逆散射方法，构造了与原QCM势具有相同壳层值的等效局域势。通过对原势和等效势的G矩阵的比较，研究了它们的离壳性质。在夸克-泡利阻塞效应较小的通道中，发现两种势的G矩阵是相似的;等效的局域势似乎模拟了QCM势。另一方面，在夸克-泡利阻塞禁止了大部分Os组态的通道中，当k&gt;1.5fm^时，由等效非定域势得到的G矩阵与原来的G矩阵有很大的不同<-1>.而且，当重子中夸克的关联被包含在组态中时，手征夸克模型可以再现正负激发重子的正确质量排序.还发现，假设u-和d-组分夸克的质量差与流夸克的质量差相同，核力的电荷对称性破缺的短程部分可以得到定量解释。

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.