Development and application of nuclear structure models to calculate double beta decay matrix elements

计算双β衰变矩阵元素的核结构模型的开发和应用

• 批准号: 5445655
• 负责人: Professor Dr. Amand Fäßler
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2007-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5445655?language=en
• 关键词: Development; application; nuclear; structure; models

To get a more accurate description of the nuclear matrix elements relevant for double beta decay, new nuclear structure methods are to be developed and applied. We are planning to develop and apply for the first time the continuum version of the QRPA (continuum-QRPA) to describe the double beta decay amplitudes. The development of such a continuum-QRPA approach is important also for other physical applications such as muon capture, muon-electron conversion, neutrino-nucleus reactions etc. Analysis based on the concept of the dynamically broken isospin and Wigner spin-isospin symmetries will shed light on the origin of the sensitive parameter dependence of the double beta decay amplitudes and will help in constraining the model parameters involved in the calculations. To estimate the effect of the many-particle configurations and thereby to bridge the gap between the QRPA and modern shell model, many-phonon states will be included into the diagonalization procedure. Reformulation of the QRPA directly in the intermediate odd-odd nuclei will help to avoid using the artificial overlap factor in calculations of the double beta decay amplitudes. Different mechanisms for the double beta decay (light and heavy neutrino exchange, right currents, etc.) are also to be analyzed.

为了更准确地描述与双β衰变相关的核矩阵元，需要发展和应用新的核结构方法。我们计划首次开发和应用连续介质版本的qRPA(Continuum-qRPA)来描述双β衰变幅度。这种连续体-qRPA方法的发展对其他物理应用也很重要，如Muon俘获、Muon-电子转换、中微子-核反应等。基于动态破裂同位旋和Wigner自旋-同位旋对称性的概念的分析将有助于揭示双β衰变幅度敏感参数依赖的起源，并有助于约束计算中涉及的模型参数。为了估计多粒子组态的影响，从而弥合qRPA和现代壳模型之间的差距，对角化过程中将包括多声子态。直接在中间奇奇核中重新表述qRPA将有助于避免在计算双β衰变幅度时使用人为重叠因子。双β衰变的不同机制(轻中微子和重中微子交换、右电流等)也是需要分析的。

项目成果

Assessment of uncertainties in QRPA $0\nu \beta \beta$-decay nuclear matrix elements

• DOI: 10.1016/j.nuclphysa.2007.06.014
• 发表时间: 2007-09
• 期刊: Nuclear Physics
• 作者: V. Rodin;P. Vogel;A. Faessler;F. Šimkovic