Shining a light on strangeness

超子对于我们理解早期宇宙、中子星以及形成物质本身的过程起着关键作用。超子是一个由三个夸克组成的复合系统。最熟悉的3夸克系统是核子--组成原子核的质子和中子。超子本质上是一个核子，其中一个或多个夸克被其较重的伙伴奇异夸克取代。在原子核中，只有核子以很大的概率存在。然而，当研究更高密度、压力或温度的系统时，更重的奇异夸克扮演着越来越重要的角色。超子被认为是重要的物体包括中子星。在重中子星中，物质可以被压缩到典型原子核密度的十倍。在这些高密度系统中，超子不断出现。理论预测，重恒星可能有类似比例的超子和核子。因此，中子星的质量、冷却机制和稳定性等基本性质在很大程度上取决于超子和核子之间相互作用的性质。然而，几十年来，关于超子-核子相互作用的可靠信息一直难以捉摸。该研究金将使超子-核子相互作用的关键数据得以获得，利用新的技术和方法，这将提高我们对中子星的性质和组成的理解。超子在宇宙的演化中也起着关键作用。早期宇宙被认为最初存在于自由夸克和胶子的等离子体中，胶子是将夸克结合在一起的强力的信使粒子。当宇宙冷却时，它经历了一个时期，一种激发的超子气体从等离子体中冻结出来（当时宇宙只有微秒的年龄）。目前，我们对这些激发超子的性质的了解还很有限。该计划将提供急需的信息，通过在实验室中生产这些状态来建立这些状态。这将限制早期宇宙的模型。受激超子的数量和性质也限制了我们对将夸克结合在一起的力的基本理解。新的理论进展最近允许从强力理论预测激发超子。我们将提供重要的数据来检验这些新的进展，增强我们现有的知识，研究方案将使用极强的高能光子束和大粒子探测器系统。实验将在美国托马斯杰斐逊国家实验室进行，该实验室是世界上此类研究的领先设施之一。

The hyperon plays a key role for our understanding of the early universe, neutron stars, and the processes responsible for forming matter itself. The hyperon is a composite system of 3-quarks. The most familiar systems of 3-quarks are the nucleons - the protons and neutrons which make up atomic nuclei. A hyperon is essentially a nucleon in which one or more of its quarks is replaced by its heavier partner, the strange quark.In atomic nuclei only nucleons exist with significant probabliity. However when studying systems at higher densities, pressures or temperatures, heavier strange quarks play an increasingly important role. Objects where hyperons are thought to be important include neutron stars. In heavy neutron stars, matter can be squashed up to ten times the density of a typical atomic nucleus. In these highly dense systems, hyperons constantly appear. Theories predict that heavy stars could have similar fractions of hyperons and nucleons. Therefore, fundamental properties of neutron stars, such as their mass, cooling mechanisms and stability heavily depend on the nature of the interaction between hyperons and nucleons. However, reliable information on the hyperon-nucleon interaction has been elusive for many decades. This fellowship will enable critical data on the hyperon-nucleon interaction to be obtained, utilising novel techniques and methods, which will improve our understanding of the properties and composition of neutron stars. Hyperons also play a key role in the evolution of the universe. The early universe is thought to have initially existed in a plasma of free quarks and gluons, where the gluon is the messenger particle of the strong force which holds quarks together. As the universe cooled it went through an epoch where a gas of excited hyperons froze out of the plasma (when the universe was only microseconds old). Currently, our knowledge of the properties of these excited hyperons is poor. The programme will deliver much needed information to establish these states by producing them in the laboratory. This will constrain models of the early universe. The number and properties of the excited hyperons also constrains our basic understanding of the forces that hold quarks together. New theoretical advances have recently allowed the excited hyperons to be predicted from the theory of the strong force. We will provide important data to test these new advances, enhancing our current knowledge.The research programme will use extremely intense beams of high-energy photons and large-particle detector systems. The experiments will take place at the Thomas Jefferson National Laboratory in the USA, one of the leading facilities in the world for such studies.