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

这项行动资助约翰霍普金斯大学的Matthew Walters于2013年夏天在日本Kashiwa的东京大学Kavli宇宙物理和数学研究所开展数学和物理科学领域的研究项目。这个项目的题目是“早期宇宙中的新光粒子”。主持的科学家是村山仁。本研究项目研究新的光粒子物种对早期宇宙现象的影响，如轻元素的合成和残余背景辐射的产生。这些效应在有效的场理论方法中进行了探讨，以便以模型独立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重组时代成为非相对论性的新光粒子的质量。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，具有发现新粒子和物理现象的潜力。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；介绍该地区的科学、科学政策和科学基础设施；以及对社会、文化和语言的了解。这些活动符合美国国家科学基金会的目标，即在其科学家、工程师和教育工作者的职业生涯早期培养国际合作，从而确保美国科学劳动力具有全球意识。此外，通过这个研究项目，研究员正在为多个观测实验的数据开发新的分析和应用。该研究员将这些结果提交发表，以帮助在使用当前和未来数据方面的实验科学合作，并利用它们教育普通大众了解物理学和天文学的当前进展。此外，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，以鼓励进一步合作和扩展该项目。

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.