Windows on the Universe: Nuclear Astrophysics at the NSCL

国家超导回旋加速器（NSCL）的核天体物理小组将利用他们的实验设备来解决关于宇宙中元素起源的长期问题。其目标是在实验室中重现在新星和超新星爆炸、合并中子星、吸积中子星、大爆炸和其他极端天体物理环境中产生新元素的相同核反应。相互作用的原子核是不稳定的，需要在NSCL的稀有同位素设施中人工产生。然后可以进行实验，在几分之一秒内产生并检测到相关的同位素。核数据将用于恒星的计算机模拟，然后面对来自不同天体物理地点的光、伽马射线、引力波和中微子的多信使天文观测。在多信使天文学时代，利用光、伽马射线、引力波和中微子来解释天文观测需要了解产生这些信使的核过程。国家科学院小组建议继续他们的实验核天体物理项目和其他设施，以提供这一重要的核物理数据。他们将利用稳定和稀有同位素光束开展协同和相互关联的实验计划，利用各种现有的实验设备，并继续发展关键实验能力。这些实验要么直接测量天体物理反应（如它们发生在新星和超新星爆炸、中子星合并、中子星吸积和其他天体物理地点），要么提供对这些反应的间接约束。在这个项目中，通过精确的核物理测量来解释多信使观测结果，将为了解极端天体物理环境下的元素合成和核物质打开一扇新的窗口。这为解决NP2010国家科学院研究和核科学长期计划中确定的核科学长期存在的问题提供了机会，包括我们在这里要解决的问题；化学元素从何而来，又是如何进化的？结构是如何在宇宙中产生的，它与恒星中元素的出现和爆炸过程有什么关系？物质在极端温度和密度下的性质是什么？以及“什么是暗物质”。这些问题将通过与核理论家和天体物理学家密切合作的实验室实验来推进我们对恒星核过程的认识。这个小组将进行实验，提供新星、x射线爆发和超新星中质子捕获的新数据。他们将测量一系列所需的核性质，以了解通过快速和中间中子捕获合成重元素的过程，研究超新星和中子星中的弱相互作用，并寻找新的核衰变模式，这可能会为大爆炸中的元素合成提供线索。更广泛的影响：核物理和天体物理交叉的研究计划将吸引不同群体的本科生、研究生和博士后，利用国家科学基金会大构想“宇宙之窗”的引人注目的科学。学生和博士后将通过利用密歇根州立大学与核天体物理联合研究所（JINA-CEE）、密歇根州立大学天文学小组和新成立的密歇根州立大学计算数学科学与工程系之间的协同联系，接受跨学科培训。这将有助于学生和博士后在学术界、工业界和美国国家实验室为成功的核事业做好准备。为了进一步提高对STEM职业的兴趣，特别是对女性和少数民族的核科学职业的兴趣，PI团队将扩大非常成功的年度核科学暑期学校。该学院为本科生提供在本国机构无法获得的核科学教育，并利用该提案中引人注目的科学来吸引和教育学生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The nuclear astrophysics group at the National Superconducting Cyclotron (NSCL) will use their experimental facilities to address long-standing questions about the origin of the elements in the Universe. The goal is to restage, in the laboratory, the same nuclear reactions that produce new elements in nova and supernova explosions, merging neutron stars, accreting neutron stars, the Big Bang, and other extreme astrophysical environments. The interacting atomic nuclei are unstable and need to be artificially produced at the NSCL rare isotope facility. Experiments can then be carried out, where the relevant isotopes are produced and detected within fractions of a second. The nuclear data will be used in computer simulations of stars that are then confronted with multi-messenger astronomical observations using light, gamma rays, gravitational waves and neutrinos from various astrophysical sites. In the era of multi-messenger astronomy the interpretation of astronomical observations using light, gamma-rays, gravitational waves, and neutrinos requires an understanding of the nuclear processes that create these messengers. The NSCL group proposes to continue their experimental nuclear astrophysics program and other facilities to provide this important nuclear physics data. They will carry out a synergistic and interconnected experimental program using stable and rare isotope beams that employs a wide variety of existing experimental equipment, and continued development of key experimental capabilities. The experiments either measure astrophysical reactions directly (as they occur in nova and supernova explosions, neutron star mergers, accreting neutron stars, and other astrophysical sites) or provide indirect constraints on the reactions. Interpreting multi-messenger observations with accurate nuclear physics measurements obtained in this program will open a new window on the universe providing insight into element synthesis and nuclear matter in extreme astrophysical environments. This provides the opportunity to address long standing questions in nuclear science identified in the NP2010 National Academy study and the nuclear science long rage plan, including the questions we aim to address here; Where do the chemical elements come from, and how did they evolve? How does structure arise in the universe and how is it related to the emergence of the elements in stars and explosive processes? What is the nature of matter at extreme temperatures and densities? and "What is dark matter". These questions will be addressed by advancing our knowledge of stellar nuclear processes through laboratory experiments in close collaboration with nuclear theorists and astrophysicists. This group will perform experiments providing new data on proton capture in Novae, X-ray bursts, and Supernovae. They will measure a range of nuclear properties needed to understand the synthesis of heavy elements by rapid and intermediate neutron capture, study weak interactions in supernovae and neutron stars, and search for new nuclear decay modes that may shed light on element synthesis in the Big Bang. Broader Impacts: The proposed program of studies at the intersection of nuclear physics and astrophysics will attract a diverse group of undergraduate students, graduate students and postdocs to nuclear science by taking advantage of the compelling science of the NSF Big Idea "Windows on the Universe". Students and postdocs will receive interdisciplinary training by taking advantage of the synergistic connections available at MSU with the Joint Institute for Nuclear Astrophysics (JINA-CEE), the MSU Astronomy group, and the new MSU Department of Computational Mathematics Science and Engineering. This will help prepare the students and postdocs for successful nuclear careers in academia, industry and the US national laboratories.To further increase interest in STEM careers in general, and nuclear-science careers specifically, especially among women and minorities, the PI team will expand the very successful annual Nuclear Science Summer School at NSCL. The School provides undergraduate students access to nuclear science education that is not available at their home institutions and takes advantage of the compelling science in this proposal to attract and educate students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.