Basic modes in nuclear collective motion

这项涉及三个主要机构的国际合作取得了以下成果：1)S最初为偶偶核引入的Q声子方案推广到了奇A核。特别是阐明了U(6|4)的超对称性结构。更准确地说，在先前的研究中，同一表象空间内的本征态是通过对每个表象的基态作用U(6|4)的四极算符而产生的。在本研究中，本征态是利用超对称算符在不同的表象之间产生的。Q声子理论已推广到其他超对称情形，如U(6|12)和U(6|20)。2)所谓的β振动态是多个β-伽马激发的混合物，特别是β激发和双伽马激发的混合。这一趋势与Koeln和Yale群的实验数据相一致。3)推广了Q声子的概念，研究了2+和3+的混合对称态。对于Mo，Xe，Ba和Pt区，Koeln群发现了许多这样的态的候选。4)提出了O(6)的不同表示之间的可能联系。5)对Xe和Ba同位素的高自旋态SRE进行了研究，包括来自Koeln群的实验数据。

The following outcome has been obtained by this international collaboration involving three major institutions.1) The Q-phonon scheme originally introduced for even-even nuclei s extended to odd-A nuclei. In particular, the structure of the supersymmetry of U(6|4) has been clarified. To be more precise, eigenstates within the same representation space were shown, in the previous study, to be produced by acting the quadrupole operator of U(6|4) on the ground state of each representation. In the present study, eigenstates are shown to be produced between different representations by utilizing supersymmetric operators. The Q-phonon theory has been extended to other supersymmetric cases like U(6|12) and U(6|20).2) The so-called beta vibrational state is shown to be a mixture of multi beta-gamma excitations, in particular, that of the beta excitation and double gamma excitation. This trend is found to be consistent with experimental data taken by the Koeln and Yale groups.3) The mixed symmetry states of 2+ and 3+ are studied by extending the idea of the Q-phonon. Many godd candidates of such states are found by the Koeln group for Mo, Xe, Ba and Pt regions.4) A possible link between different representations of O(6) is suggested.5) High spin states sre studied for Xe and Ba isotopes including experimental data from the Koeln group.