Nuclear Magnetic and Gamow-Teller Transitions

核磁矩和衰变的研究在研究核结构和有效相互作用方面起着非常重要的作用。近年来，关于质子和电子散射中的磁跃迁和伽莫夫-泰勒跃迁，准弹性电子散射中的纵向和横向响应等方面的信息已经得到了大量的研究。我们研究了核极化，特别是张量相关、介子交换电流、<DELTA>-空穴激发和夸克自由度对上述反应的影响。在磁跃迁和伽莫夫-泰勒跃迁中，已知跃迁强度分布在高能激发区内。然而，从理论上阐明这种分配的机制是非常困难的。我们发展了扩展的修正随机相位近似，它考虑了基态相关和交换电流的影响。我们还研究了准弹性区的自旋-同位旋响应。这里采用了连续体RPA理论。如何包含交换项是一个新发展的方法。我们得到了不同于其他核物质计算的结果。我们还将带有交换项的连续谱RPA应用于电子散射的库仑和规则。

Study of the nuclear magnetic moments and beta-decay played a very important role in studying nuclear structure and effeetive interactions. Resently a lot of information about magnetic and Gamow-Teller transitions observed in proton and electron scatterings, londitudinal and transverse responses in the quasi-elastic electron scalterings etc. has been obtained. We have studied the effects of core polarization, especially tensor correlations, meson exchange currents, <DELTA>-hole excitations and quark degrees of freedom on the above reactions. In the magnetic and Gamow-teller transitions, it has been known that the transition strengths have been distributed over the high energy excitation regions experimentally. It was, however, very difficult to clarify the mechanism of the distribution theoretically. We have developed the extended modified Rondom Phase Approximation which takes into account the effect of grount state corretlations and exchange currents.We have also studied the spin-isospin response in the quasi-elastic region. Here the continuum RPA theory has been employed. The method how to include the exchange term has been newly developed. We have obtained the results which are different from other calculations in nuclear matter. We have also applied the continuum RPA with exchange terms on the coulomb sum rule in the electron scattering.