Origin of mass scales and hierarchies

随着大型强子对撞机运行的临近，正在认真考虑的新物理模型的数量从未像现在这样多。需要新的物理学来完成我们关于自然界四种力量中的两种力量统一的图景，就像几十年前的弱电相互作用标准模型所描述的那样。这种描述中固有的对称性破缺需要一个新的质量标度的出现，但对于这个质量标度的起源还没有确凿的理解。QCD的质量标度大约比电弱标度低三个数量级，描述了自然界的第三种基本力。对于QCD，自然提供了一个例子，说明在强相互作用规范理论中，质量标度如何具有动力学起源。令人惊讶的是，大多数关于弱电质量标度起源的建议与QCD的例子有很大的不同。流行的提议涉及在自然界中还没有见过的概念(初等标量场、超伙伴、额外维度、弦理论等)。我的研究追求一种更保守的方法，更符合QCD提供的线索。我将继续详细阐述这可能对大型强子对撞机物理意味着的信号，我将继续研究对剩余的质量和味道问题的相关影响。一个耐人寻味的可能性是，强规范相互作用也削弱了万有引力，这是自然的第四种力量。这是通过“诱导引力”现象实现的，它需要更好地理解像无质量QCD这样的理论中的真空能量。有助于这一理解的是来自实验、晶格研究和其他非微扰方法的低能QCD的最新结果。

As the operation of the LHC looms near, the number of new physics models being seriously considered has never been greater. New physics is needed to complete our picture of the unification of the two of the four forces of nature as described by the decades old standard model of electroweak interactions. The symmetry breaking inherent in this description requires the appearance of a new mass scale, but there has been no confirmed understanding of the origin of this mass scale. At about three orders of magnitude lower in energy than the electroweak scale is the mass scale of QCD, describing a third fundamental force of nature. With QCD nature provides an example of how a mass scale can have a dynamical origin in a strongly interacting gauge theory. Surpisingly, most proposals for the origin of the electroweak mass scale differ significantly from the QCD example. The popular proposals involve concepts that have not yet been seen in nature (elementary scalar fields, superpartners, extra dimensions, string theories, etc.). My research pursues a more conservative approach, more in line with clues provided by QCD. I will continue to elaborate on the signals that this may imply for LHC physics and I will continue to study the related implications for the remaining questions of mass and flavor. An intriguing possibility is the idea that strong gauge interactions also underly gravitation, the fourth force of nature. This is through the phenomenon of "induced gravity", and it requires a better understanding of vacuum energy in theories like massless QCD. Contributing to this understanding are recent results from experiment, lattice studies, and other nonperturbative approaches to low energy QCD.