U.S.-Japan Cooperative Research: Mass Measurements of rp-Process Nuclei Near the Proton Drip Line

该奖项促进了由美国主导的核天体物理学实验项目的启动，并促进了日本RIKEN放射性离子束工厂（RIBF）在核天体物理学方面的国际合作，RIBF被认为是世界上最杰出的放射性离子束设施。元素的起源仍然是核物理学中最大的未解之谜之一。特别是涉及原子核远不稳定的核合成过程（rp-和r-过程）在很大程度上仍未经过测试。这项美日合作的实验将测量与天体物理rp过程相关的原子核质量，rp过程被认为是x射线爆发的燃料。这些质量将使用tof技术进行测量；也就是说，在光束中已知动量的原子核的飞行时间将在光束线上两点之间测量。了解这些核质量将有助于更好地理解x射线爆发的光发射剖面。在日本的主要合作者包括RIBF的Toshiyuki Kubo，东京大学的Shigeru Kubono和东京大学的Toshitaka Kajino。四名美国研究生和一名博士后研究员将参与该项目，该项目由国际科学与工程办公室和物理系共同资助。该奖项还支持美国和日本科学家之间长期国际合作的下一阶段规划。

OISE-0735989 (Famiano)AbstractThis award facilitates the initiation of a U.S.-led experimental program and international collaboration in nuclear astrophysics at Japan's RIKEN Radioactive Ion Beam Factory (RIBF), regarded as the most outstanding radioactive ion beam facility in the world. The origin of the elements remains one of the largest unanswered questions in nuclear physics. In particular, nucleosynthesis processes involving nuclei far from stability (the rp- and r-processes) remain largely untested. The experiment in this U.S.-Japan collaboration will measure the masses of atomic nuclei relevant to the astrophysical rp-process, the nuclear process thought to fuel x-ray bursts. These masses will be measured using the TOF-technique; that is, the time-of-flight of nuclei of known momentum in the beam will be measured between two points in the beamline. Knowing these nuclear masses will allow a better understanding of the light emission profile in an x-ray burst. Primary collaborators in Japan include Toshiyuki Kubo of the RIBF, Shigeru Kubono of the University of Tokyo, and Toshitaka Kajino of the University of Tokyo. Four U.S. graduate students and one post-doctoral researcher will participate in the project, which is jointly funded by the Office of International Science & Engineering and the Division of Physics. The award also supports planning for the next stage of a longer-term international collaboration between scientists in the United States and Japan.