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

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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.