Nuclear, Particle, and Weak Interaction Physics of the Big Bang and Stellar Collapse

这个项目的学术价值在于它的主要目标：一方面利用核物理和中微子物理之间令人兴奋的协同作用，另一方面探索天体物理环境的动力学/核合成，从而探索原子核和中微子的基本物理。中微子和强相互作用物理/核的相互关联的物理学是当前理论的核心，这些理论涉及早期宇宙中轻核和重子/轻子数的起源，恒星塌缩事件中重核的起源，超新星的动力学，甚至可能是暗物质/能量问题。核物理学和核天体物理学站在当前两大科学趋势的接触点上：(1)中微子物理学正在进行的实验驱动的革命；(2)观测天文学能力，特别是宇宙学方面的最新惊人进展。这是通过相互联系推进基础中微子/核物理以及天体物理学和宇宙学的一个巨大机会。该项目支持的工作将旨在利用这一机会。事实上，在过去的三个资助周期中，PI和他的研究生们已经发现了一些基本的弱相互作用/中微子/核物理与天体物理学、早期宇宙物理学、引力坍缩物理学、核合成，特别是中微子？阿沃尔变换和动力学/核合成之间的可能联系。事实证明，这是研究生(9年7名博士，所有人都有核物理研究职位，5名拥有终身教职或终身教职轨道职位)和本科生(6名REU本科生)的极好培训场所。该项目将使优秀学生的继续培训成为可能。再加上国际和平研究所的研讨会/宣传和出版物，这就构成了该项目对科学产品以外的更广泛的影响。可以说，现在测量了中微子的质量平方差和真空混合角(13个除外)。这个项目的一个关键目标是评估和计算这一新知识对早期宇宙物理、引力坍缩和核合成模型的影响。一些中微子的性质，如违反CP的相(ES)和13仍然没有测量到。这里的一个目标是评估这些量在天体物理环境中的作用，着眼于限制。归根结底，中微子质量和混合光谱的全部范围，特别是关于右手状态，仍然是个谜。由于宇宙学参数(例如，从宇宙微波背景(CMB)各同位素得出的)和中微子性质受到如此严格的约束，例如，正在进行的迷你Boone实验中的积极结果可能表明存在与活性物种混合的轻SU(2)单重态“不育”中微子。这也可能标志着一个大的净轻子数的存在(S)，并呼吁对现有的恒星坍塌、重元素核合成、中微子在暗物质/能量中的作用以及重子数的起源进行激进的讨论。最近对超级贫金属晕星的观测使我们对挑战现有模型的r过程有了新的见解(例如，太阳系丰度模式似乎对核质量100是普遍的)。

The intellectual merit of this project rests on its principal goal: to probe the fundamental physics of nuclei and neutrinos by exploiting the exciting synergy between nuclear physics and neutrino physics on the one hand, and the dynamics/nucleosynthesis of astrophysical environments on the other. The interrelated physics of neutrinos and strong interaction physics/nuclei is at the heart of current theories for the origin of the light nuclei and the baryon/lepton numbers in the early universe, the origin of the heavy nuclei in stellar collapse-based events, the dynamics of supernovae, and potentially even the dark matter/energy problems. Nuclear physics and nuclear astrophysics stand at the contact point of two great current trends in science: (1) the ongoing experimentally driven revolution in neutrino physics; and (2) the startling recent advances in the capabilities of observational astronomy, especially in cosmology. This represents a tremendous opportunity for advancing both fundamental neutrino/nuclear physics and astrophysics and cosmology through their interconnection. The work supported by this project will aim at exploiting this opportunity. In fact, the PI and his graduate students over the last three funding cycles have discovered a number of these connections between fundamental weak interaction/neutrino/nuclear physics and the frontiers of astrophysics, in early universe physics, the physics of gravitational collapse, nucleosynthesis, and especially the possible connections between neutrino ?avor transformation and dynamics/nucleosynthesis. This has proven to be an excellent training ground for graduate students (7 PhD's in 9 years, all of whom have positions in nuclear physics research, and 5 have tenured or tenure track positions) and undergraduates (6 REU undergraduates). This project will enable the continuing training of excellent students. Coupled with the PI's seminars/outreach and publications, this constitutes the broader impact of this project beyond the scientific product. Arguably, the mass-squared differences and vacuum mixing angles (save for 13) of the neutrinos are now measured. A key goal of this project is to assess and calculate the impact of this new knowledge on models for the physics of the early universe, gravitational collapse, and nucleosynthesis. Some neutrino properties, like the CP-violating phase(es) and 13 remain unmeasured. A goal here will be to assess the role of these quantities in astrophysical environments with an eye toward constraints. Ultimately, the full extent of the neutrino mass and mixing spectrum, especially regarding right-handed states remains mysterious. Because the cosmological parameters (e.g., as derived from the Cosmic Microwave Background (CMB) anisotopies) and neutrino properties are so tightly constrained, a positive result in the on-going mini-BooNE experiment, for example, could signal the existence of a light SU(2) singlet 'sterile' neutrino which mixes with active species. This might also signal the existence of a large net lepton number(s) as well as call for a radical overhall of existing models for stellar collapse, heavy element nucleosynthesis, the role of neutrinos in dark matter/energy, and the origin of the baryon number. Observations of Ultra Metal Poor halo stars recently have given us new insight into the r-process which challenge existing models (e.g., the solar system abundance pattern seems to be universal for nuclear masses 100). The PI and his students will direct analytic and numerical calculations toward: (1) an understanding of active-active and active-sterile channel neutrino flavor transformation in the early universe as regards big bang nucleosynthesis and lepton number generation/destruction/limits, CMB derived neutrino mass limits, supernova shock re-heating, r-process nucleosynthesis, the supernova neutrino signal, and all with emphasis on insight into the newly discovered fixed point solution for the nonlinear neutrino-neutrino forward scattering 'background' potential in the active-active neutrino/antimeutrino conversion channel; (2) a further study of neutrino-nucleus interactions in stellar collapse/heavy element nucleosynthesis, including de-excitation of hot nuclei into neutrino pairs and neutrino capture-induced fission, as well as a consistent treatment of the relationship between the high temperature nuclear partition function and the weak strength distribution in nuclei; (3) studies directed toward better constraints on sterile neutrino dark matter from better knowledge of the physics of the QCD epoch in the early universe, from future x-ray observatories, and from the effects of these particles in post-supernova explosion neutron stars, especially the way in which the neutrino potentials which the govern de-coherence production of these heavy states evolve with time; (4) exploring the role of dynamical neutrino mass generation in cosmology; (5) studies of high neutron excess r-process nucleosynthesis with fission cycling.