Searching for New Physics in the Lab and the Sky

该奖项资助纽约大学肯·范·蒂尔伯格教授的研究活动。当前的一套物理定律——被封装在粒子物理学和宇宙学的标准模型中——对自然界中所有已知的现象提供了极其准确和精确的描述。然而，仍然存在一些谜题。最明显的缺点是，暗物质的微观性质是未知的，尽管通过其引力影响有大量证据证明它的存在，但暗物质是一种惰性成分，构成了银河系和宇宙的大部分物质密度。在他的研究中，Van Tilburg教授的目标是开发比以前探测到的更小的暗物质结构的观测探测器，使用基于由小而不可见的暗物质团块引起的星光引力偏转的方法。利用x射线卫星和地面暗物质实验，他还将致力于探测弱相互作用的低质量粒子，这是一类产生于恒星核心的暗物质候选者。这一领域的研究通过寻求回答物理学中最基本的问题之一，即理解构成暗物质的粒子，从而促进了国家利益。Van Tilburg教授还将让研究生和博士后参与他的研究，从而在这个新兴的粒子物理学和天体物理学交叉领域培养下一代的初级科学家。他还将访问当地的高中，就粒子物理学和宇宙学进行公开讲座，并教育来自弱势群体的学生追求科学职业道路。在第一个研究途径中，Van Tilburg教授和他的团队将对公共天文数据集进行一系列时域、天体测量、弱引力透镜分析，以寻找比1亿个太阳质量轻的完全不发光的暗物质结构。特别是，他的目标是开发一个数据分析管道，以从超致密暗物质结构以及天体物理致密残留物和黑洞中搜索盖亚时间序列数据中的瞬态天体测量偏转。他还试图分析天体固有运动的相关变化和背景源的加速度，这些变化是由更广泛的暗物质结构的引力透镜引起的。对这种小尺度结构的（非）探测将为暗物质的微物理学以及小尺度结构形成的原始种子提供至关重要的新限制。在第二条研究途径中，Van Tilburg教授将研究最近引入的一种被称为“恒星盆地”的现象，在这种现象中，弱耦合粒子可以从整个恒星体积中发射到密度随时间积累的束缚轨道上。这种效应对任何类型的粒子都是通用的，如果粒子的静止质量能量与恒星内部的温度相差不远，这种效应就很重要。Van Tilburg推测，与恒星盆地相关的现象——在实验室中直接探测和在望远镜观测中间接探测——将形成对质量范围从几电子伏特到数百电子伏特的任何粒子的领先探测。本研究途径的目标是详细地研究这一现象：计算所有的生产机制，对可观察到的信号进行计算，分析公开可用的数据，并根据模型的参数空间解释结果。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。

This award funds the research activities of Professor Ken Van Tilburg at New York University. The current set of physical laws --- as encapsulated within the Standard Models of Particle Physics and Cosmology --- provide an exquisitely accurate and precise description of all known phenomena in nature. However, several puzzles still remain. The most tangible shortcoming is that the microscopic nature of dark matter, a mostly inert component comprising most of the matter density of the Galaxy and the Universe, is unknown, despite the troves of evidence for its existence through its gravitational influence. In his research, Professor Van Tilburg aims to develop observational probes of dark-matter structures smaller than ever detected before, using methods based on the gravitational deflection of starlight caused by small and otherwise invisible clumps of dark matter. Using X-ray satellites and terrestrial dark matter experiments, he will also aim to detect weakly-interacting low-mass particles, a motivated class of dark-matter candidates which are produced in the cores of stars. Research in this area advances the national interest by seeking to answer one of the most fundamental questions in physics, namely that of understanding what particle(s) comprise the dark matter. Professor Van Tilburg will also involve graduate students and a postdoc in his research, thereby training the next generation of junior scientists in this burgeoning new field at the intersection of particle physics and astrophysics. He will also visit local high schools to give public lectures about particle physics and cosmology and to educate students from underrepresented groups about pursuing scientific career paths. In a first research avenue, Professor Van Tilburg and his group will conduct a suite of analyses of time-domain, astrometric, weak gravitational lensing on public astronomical data sets, to search for entirely non-luminous dark matter structures lighter than 100 million solar masses. In particular, he aims to develop a data analysis pipeline to search for transient astrometric deflections in Gaia time-series data from ultra-compact dark-matter structures as well as from astrophysical compact remnants and black holes. He also seeks to analyze the correlated shifts in celestial proper motions and accelerations of background sources induced via gravitational lensing by more extended dark-matter structures. A (non-)detection of such small-scale structures would provide crucial new constraints on the microphysics of dark matter, as well as the primordial seeds of structure formation on small scales. In a second research avenue, Professor Van Tilburg will study a recently introduced phenomenon, dubbed "stellar basins", wherein weakly-coupled particles can be emitted from the entire stellar volume onto bound orbits whose density accumulates over time. This effect is generic for any particle type and important if the particle has a rest-mass energy not too far removed from the temperature in the stellar interior. Van Tilburg conjectures that phenomena associated with stellar basins --- direct detection in the laboratory and indirect detection in telescope observations --- will form the leading probes of any particle in the mass range from a few eV to hundreds of keV. The objective of this research avenue is to work out this phenomenology in detail: calculating all production mechanisms, performing computations for the observable signals, analyzing publicly available data, and interpreting the results in terms of the parameter space of the models.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.