Determination of astrophysical rates for reaction involving light unstable nuclei relevant to nucleosynthesis in novae and super novae

分析了RIKEN加速装置提供的快速RI光束的实验结果，并对未来的研究进行了考虑。基于^<23>Al束和^<27>P束的库仑解离实验结果，确定了爆炸氢燃烧过程的天体物理反应速率。在温度和密度下，得到了质子俘获比正电子衰变快的临界条件。通过与新星和x射线爆发的天体物理模型进行比较，结果表明，正电子衰变在新星中占主导地位，而质子捕获在x射线爆发中很重要。2)库仑解离反应机理研究除铅靶外，还以液氢和氦靶进行了^8B裂解实验，提取了M1、E2和核激发组分的量。他们的结果表明，更有必要准确地从库仑解离中提取质子捕获截面。利用光势模型对提取的弹性散射角分布进行了分析。特别是，前文计算中使用的势能很好地再现了铅靶的数据，证实了前文的分析。通过与理论学家的讨论，可以通过微观反应计算的多步过程效应来理解直接解离与库仑解离实验结果之间存在的差异。3) M1跃迁概率提取方法的发展在许多涉及爆炸性氢燃烧的反应中，M1和E2组分混合的跃迁是很重要的。考虑了用精确的角分布测量从库仑解离数据中分离出Ml组分的可能性。在模拟计算的基础上，对其有效性进行了检验，并提出了一个新的实验，并在日本理化研究所得到了批准。少

Experimental results with fast RI beams provided by the RIKEN accelerator facility have been analyzed, and considerations for future studies were made.1) Proton capture reactions in the rp process studied by the Coulomb dissociation methodBased on the experimental results of the Coulomb dissociation experiments with ^<23>Al and ^<27>P beams, astrophysical reaction rates for explosive hydrogen burning processes have been determined. The critical condition in the temperature and density where the proton capture becomes faster than the positron decay was obtained. In comparison with astrophysical models for novae and X-ray bursts, it turned out that positron decays dominate in novae whereas proton capture is important in X-ray bursts.2) Reaction mechanism study on Coulomb dissociationExperiments of ^8B breakup have been performed with liquid hydrogen and helium targets in addition to a lead target, in order to extract the amount of M1, E2 and nuclear excitation components. Their results a … More re necessary to accurately extract the proton capture cross section from Coulomb dissociation. Extracted elastic scattering angular distributions were analyzed with the optical potential model. Especially, the data for the lead target were well reproduced by the potential used in the previous calculation, confirming the earlier analysis. Through discussions with theorists, existing difference between the results from the direct and Coulomb dissociation experiments may be understood by the effect of multi step processes by microscopic reaction calculations.3) Development of the method to extract M1 transition probabilityIn many reactions involved in explosive hydrogen burning, transitions with mixture of M1 and E2 components are important. Possibility of resolving the Ml component from dominant E2 in Coulomb dissociation data with precise angular distribution measurements has been considered. Based on a simulation calculation, its usefulness was examined and a new experiment has been proposed and approved at RIKEN. Less