New and Refurbished Directions Beyond the Standard Model

该奖项资助在哈佛大学丽莎兰德尔教授的研究小组工作的博士后研究助理的研究活动。近几十年来，粒子物理学取得了重大进展。然而，许多问题仍然顽固地存在，似乎需要新的成分或新的思维方式。在这些问题中，有一个粒子物理学中所谓的“层次问题”，为什么引力如此微弱的问题 还有一些关于宇宙能量密度的问题，这些问题直接影响到宇宙在大爆炸后膨胀的速度，以及它今天似乎在加速膨胀的速度。 作为她的研究的一部分，兰德尔教授认为，在这些理论中，有额外的时空维度超出了宽度，高度和深度。 这些额外的维度提供了一个新的竞技场，在其中可以解决这些和其他问题。 因此，这一领域的研究通过增进我们对宇宙基本运作的理解，符合国家利益。 预计这项研究也将产生更广泛的影响。 额外维度的研究不仅提供了对粒子物理学当前思想的更深入的了解，而且还为进入该领域的初级物理学家（如博士后研究员和学生）的培训提供了一个丰富的领域。 这项研究还将提供公众喜欢学习的想法，兰德尔教授将在她正在进行的公开讲座中包括这些想法。从技术上讲，这项研究将涉及在具有额外时空维度的理论背景下出现的新特征。特别是，对于实现三个观测空间维度的宇宙学至关重要的稳定机制如何改变描述我们所看到的低能理论？ 已经有一些例子，最终基于弦理论模型，来自额外维度的引力约束是必不可少的，需要包括在分析中。 作为该项目的一部分，兰德尔教授和她的同事们将研究这种额外的成分如何与实现理论的一致性和确定额外维度的大小相关。该奖项反映了NSF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 a postdoctoral research associate working in the research group of Professor Lisa Randall at Harvard University.Recent decades have seen significant advances in particle physics. Yet many issues stubbornly remain that seem to require new ingredients or new ways of thinking. Among these problems is the so-called "hierarchy problem" of particle physics --- i.e., the question of why gravity is as weak as it is. There are also problems concerning the energy density of the Universe --- problems which directly affect how quickly the universe expanded immediately after the big bang and how quickly it appears to be accelerating in its expansion today. As part of her research, Professor Randall considers theories in which there are extra spacetime dimensions beyond those of width, height, and depth. Such extra dimensions provide a new arena in which these and other issues may be addressed. Research in this area thus serves the national interest by enhancing our understanding of the fundamental operation of the universe. This research is also expected to have significant broader impacts. Studies of extra dimensions not only provide deeper insights into current ideas of particle physics but also offer a rich territory ideal for the training of junior physicists entering the field, such as postdoctoral fellows and students. This research will also provide ideas that the public enjoys learning about, and which Professor Randall will include in her ongoing public lectures. More technically, this research will involve new features that appear within the context of theories with extra spacetime dimensions. In particular, how does the stabilization mechanism essential to achieving the cosmology of the three observed spatial dimensions change the low energy theory that describes what we see? Already there exist examples, ultimately based on a string theory model, where gravitational constraints from an extra dimension were essential and needed to be included in the analysis. As part of this project Professor Randall and her colleagues will study how this extra ingredient can be relevant for achieving the consistency of the theory and fixing the size of an extra dimension.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.