NSF East Asia and Pacific Summer Institute (EAPSI) for FY 2013 in Japan

这一行动资助约翰霍普金斯大学的马修·沃尔特斯于2013年夏天在日本鹿儿和的东京大学卡夫利宇宙物理和数学研究所开展了一个数学和物理科学领域的研究项目。该项目的标题是“早期宇宙中的新轻粒子”。这项研究项目研究了新的轻粒子物种对早期宇宙现象的影响，如轻元素的合成和残留背景辐射的产生。这些影响是以一种有效的场论方法来探索的，以便以一种与模型无关的方式对理论提供约束。此外，该项目还开发了计算方法，以确定在电子和质子开始形成中性原子的复合时代变得非相对论的新轻粒子的质量。这些结果对宇宙学和基本粒子物理学的理论模型和未来的实验研究具有重要意义，有可能发现新的粒子和物理现象。EAPSI奖学金的广泛影响包括为研究员提供美国以外的第一手研究经验；介绍各自所在地的科学、科学政策和科学基础设施；以及对社会、文化和语言的定位。这些活动符合NSF的目标，即在其科学家、工程师和教育工作者的职业生涯早期为国际合作进行教育，从而确保拥有一支具有全球意识的美国科学队伍。此外，通过这一研究项目，该研究员正在为来自多个观测实验的数据开发新的分析和应用程序。这位研究员提交了这些结果以供出版，以帮助实验科学合作使用当前和未来的数据，并利用这些结果教育普通民众了解物理学和天文学的当前进展。此外，该研究员正在与东道国和美国的研究人员分享这些分析方法，以鼓励该项目的进一步合作和扩展。

This action funds Matthew Walters of Johns Hopkins University to conduct a research project in the Mathematical and Physical Sciences area during the summer of 2013 at the University of Tokyo's Kavli Institute for the Physics and Mathematics of the Universe in Kashiwa, Japan. The project title is "New Light Particles in the Early Universe." The host scientist is Hitoshi Murayama.This research project studies the effects of new light particle species on early universe phenomena, such as the synthesis of light elements and the production of residual background radiation. These effects are explored in an effective field theory approach, in order to provide constraints on theories in a model-independent fashion. In addition, this project develops calculational methods to determine the mass of new light particles which become nonrelativistic during the era of recombination, when electrons and protons began to form neutral atoms. These results have significant implications for theoretical models and future experimental research, both in cosmology and elementary particle physics, with the potential to discover new particles and physical phenomena.Broader impacts of an EAPSI fellowship include providing the Fellow a first-hand research experience outside the U.S.; an introduction to the science, science policy, and scientific infrastructure of the respective location; and an orientation to the society, culture and language. These activities meet the NSF goal to educate for international collaborations early in the career of its scientists, engineers, and educators, thus ensuring a globally aware U.S. scientific workforce. Furthermore, through this research project the Fellow is developing new analyses and applications for data from multiple observational experiments. The Fellow is both submitting these results for publication to aid experimental scientific collaborations in the use of current and future data and using them to educate the general population about current progress in physics and astronomy. In addition, the Fellow is sharing these methods of analysis with researchers in the host country and the U.S. to encourage further collaborations and extensions of this project.