GlueX-Canada: The physics of confinement probed through gluonic excitations

粒子物理学试图在最基本的层面上理解自然及其所有定律，直至其基本成分及其相互作用。在过去的几十年里，利用加速器和天体物理观测已经取得了巨大的进步，这加强了我们的信念，即基本模型，也被称为标准模型（SM），本质上是对亚原子世界的有效描述。它的成功基本上是基于渐近自由的概念，该概念规定，夸克，最基本的粒子，在它们的分离很小（高能碰撞）时表现为自由粒子，这样就可以对它们的相互作用进行精确的分析计算。然而，当夸克结合在一起形成我们所知道的物质时，它们的相互作用是如此强烈，以至于它们不能分开，也不能作为单个夸克存在。这是一个实验事实，它给SM增加了一个额外的方面，即夸克的限制。它仍然是物理学中突出的问题之一。在约束制度中，分析计算是不可实现的，模型必须按照实验数据的要求，自由地调整输入，以便了解手头问题的基本方面。为了使我们对约束的真正性质有一个坚实的了解，高质量和可靠的实验数据是绝对必要的。这项提议的目标是创造和识别奇异形式的物质，就其本质而言，它们在所有其他粒子中表现出独特的特征，这将允许以最严格的方式测试约束的理论模型。这是一项艰巨的任务，需要实验条件，现在在加速器和光传感器技术中都成为可能。后者由加拿大小组推动，在医学物理和成像方面有重要应用。

Particle physics seeks to understand nature - and all its laws - at the most fundamental level, down to its elementary constituents and their interactions. Tremendous strides have been made in the last several decades using accelerators and astrophysical observations - that have strengthened our conviction that the basic model, also known as the Standard Model (SM), is essentially a valid description of the subatomic world. Its success is based fundamentally on the concept of asymptotic freedom, which stipulates that the quarks, the most elemental particles, behave as free particles when their separation is small (high energy collisions) so that accurate analytical calculations of their interactions can be made. However, when the quarks are bound together to form matter as we know it, their interactions are so strong that they cannot be separated and cannot exist as individual quarks. This is an experimental fact that imposes an additional aspect to the SM, that of confinement of quarks. It remains one of the outstanding problems in physics. In the confinement regime, where analytical calculations are not feasible, models have to be constructed with the freedom to adjust inputs - as required by the experimental data - in order to learn about fundamental aspects of the problem at hand. For this to lead to a solid understanding of the true nature of confinement, high quality and reliable experimental data are absolutely necessary. The goal of this proposal is to create and identify exotic forms of matter that, by their very nature, exhibit unique signatures among all other particles that will allow theoretical models of confinement to be tested in the most constraining possible way. This is a difficult task requiring experimental conditions that are now becoming possible, both in accelerator and photo-sensor technologies. The latter is driven by the Canadian group and has important applications in medical physics and imaging.