Strange Meson and Baryon Photoproduction

这项研究的目标是了解不同类型的夸克如何结合在一起形成短暂的粒子。这些数据帮助物理学家更多地了解被称为量子色动力学或简称QCD的强力的基本理论。这与在原子核内将质子和中子结合在一起的力是相同的。这里研究的粒子有一个更重的夸克，称为奇夸克，它并不是孤立在稳定的原子核中发现的。相反，这些粒子是利用伽马射线束(高能光子)与固定的质子目标碰撞产生的能量，称为光生产物。寻找具有奇怪夸克的粒子的原因是，具有重夸克的粒子的性质比只有轻夸克的粒子更容易计算。尽管奇特粒子在自然界中并不丰富，但它们帮助我们了解QCD的理论计算，这也适用于稳定粒子和所有原子核。这项研究的更广泛影响是推进技术和培养年轻科学家。技术的进步来自于建造新的粒子探测器，例如杰斐逊实验室正在建造的CLAS12探测器中的预淋浴热量计。这个探测器测量撞击它的带电粒子的能量。新材料，如波长移动光纤，以及高速电子设备，是用于该探测器的技术的一部分，该探测器由美国国家科学基金会提供部分资金。包括本科生和研究生在内的年轻科学家正在帮助建造和测试探测器。该项目过去的毕业生继续在美国和国外的其他实验室、大学和私营企业工作。

The goal of this research is to learn how different types of quarks can combine to form short-lived particles. These data help physicists to understand more about the fundamental theory of the strong force, called quantum chromodynamics or QCD for short. This is the same force that binds together protons and neutrons inside the nucleus of an atom. The particles being studied here have a heavier quark, called the strange quark, which is not found isolated in a stable nucleus. Instead, these particles are created using the energy of a collision between a beam of gamma-rays (high-energy photons) and a stationary target of protons, called photoproduction. The reason to look for particles with the strange quark is that the properties of particles with heavy quarks are easier to calculate than are particles with only light quarks. Even though strange particles are not abundant in nature, they help us understand the theoretical calculations of QCD, which also apply to stable particles and the nuclei of all atoms.The broader impact of this research is to advance technology and to train young scientists. Advances in technology come from building new particle detectors, such as the Pre-shower Calorimeter which is part of the CLAS12 detector being constructed at Jefferson Lab. This detector measures the energy of charged particles that strike it. New materials, such as wavelength-shifting optical fibers, along with high-speed electronics are part of the technology used for this detector, which is funded in part by the NSF. Young scientists, both at the undergraduate and graduate levels, are helping to construct and test the detector. Past graduates of this program have gone on to work at other laboratories, universities and private industry, both in the USA and abroad.