Proposal to Instrument an Endcap Electromagnetic Calorimeter for Spin Physics with STAR at RHIC

建议在 RHIC 上使用 STAR 测量自旋物理端盖电磁热量计

• 批准号: 9971947
• 负责人: Steven Vigdor
• 金额: $ 235万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9971947&HistoricalAwards=false
• 关键词: Proposal; Instrument; Endcap; Electromagnetic; Calorimeter

9971947Vigdor These funds will be used to construct a detector that will enable a qualitative advance in understanding of the internal structure ofprotons. Protons are known to be composed of smaller particles called quarks, antiquarks and gluons, particles that have never been observed in isolation. The contributions of the gluons and the antiquarks to the proton's properties are important, but elusive. For example, it has been inferred that the gluons dominate the mass of the proton, and hence the mass of the universe. One goal of research with this new detector is to measure the contributions of gluons and antiquarks to the proton's overall spin, a fundamental property associated with its intrinsic magnetism. These measurements are critical because other experiments performed during the past decade have suggested that the quarks and antiquarks combined account for less than a third of the knownproton spin. The detector proposed is an Endcap Electromagnetic Calorimeter (EEMC) to be added to the major STAR (Solenoidal Tracker at RHIC) detector system currently being commissioned at the new Relativistic Heavy Ion Collider facility. RHIC and STAR were originally designed to search for new phases of strongly interacting matter in collisions of very energetic heavy nuclei. The EEMC wouldcritically enhance their capabilities as a platform for a complementaryclass of experiments, utilizing colliding beams of spin-polarizedprotons at unprecedentedly high energies. It would do so by providing detection of high-energy gamma rays, electrons, positrons and neutral pi-mesons in a kinematic regime of optimal sensitivity to unmeasured contributions to the proton's intrinsic spin. The enhanced STAR detector would allow the world's best measurement of the integral gluon spin contribution, by detecting gamma rays from hard polarized proton collisions in coincidence with "jets" of hadrons -- products when a polarized quark in one proton beam strikes a polarized gluon in the other. In addition, the EEMC will facilitate important tests of the Standard Model of elementary particle properties, including the fundamental theory (quantum chromodynamics) of the interactions among quarks, antiquarks and gluons.

9971947 Vigdor这些资金将用于建造一个探测器，该探测器将使对质子内部结构的理解取得质的进步。 众所周知，质子是由称为夸克、反夸克和胶子的较小粒子组成的，这些粒子从未被孤立地观察过。 胶子和反夸克对质子性质的贡献很重要，但却难以捉摸。 例如，有人推断胶子支配质子的质量，因此支配宇宙的质量。 使用这种新探测器的研究目标之一是测量胶子和反夸克对质子整体自旋的贡献，这是与其内在磁性相关的基本性质。 这些测量是至关重要的，因为在过去十年中进行的其他实验表明，夸克和反夸克加起来不到已知质子自旋的三分之一。建议的探测器是一个端盖电磁量能器（EEMC），将添加到主要的星星（螺线管跟踪RHIC）探测器系统，目前正在委托在新的相对论重离子对撞机设施。 RHIC和星星最初设计用于在高能重核碰撞中寻找强相互作用物质的新相。 EEMC将极大地增强它们作为补充类实验平台的能力，利用前所未有的高能量的自旋极化质子碰撞束。 它将通过提供对高能伽马射线、电子、正电子和中性π介子的探测来实现这一目标，这些高能伽马射线、电子、正电子和中性π介子的运动学机制对质子固有自旋的未测量贡献具有最佳灵敏度。 增强型星星探测器将通过探测与强子“喷流”同时发生的硬极化质子碰撞产生的伽马射线，实现世界上对整体胶子自旋贡献的最佳测量--强子“喷流”是一个质子束中的极化夸克撞击另一个质子束中的极化胶子产生的产物。 此外，EEMC将促进基本粒子性质的标准模型的重要测试，包括夸克，反夸克和胶子之间相互作用的基本理论（量子色动力学）。