Forward Meson Production and Spin Asymmetries at RHIC

质子的高能结构和高能质子-质子相互作用依赖于底层夸克和胶子的自旋和角动量。布鲁克海文相对论重离子对撞机(RHIC)提供了独特的工具，使研究质子成分的自旋在极化质子碰撞中的作用成为可能。RHIC是第一台高能极化质子对撞机，在那里，实验者可以在高能质子碰撞之前准备它们的自旋取向。在质心能量高达500GeV的恒星探测器上研究了这些极化的质子碰撞。当相对论质子碰撞时，它们会产生高能碎片，包括中性介子、粒子等和粒子喷流。它是在粒子产生对质子自旋方向最敏感的最前沿区域。这项研究涉及测量相对论质子-质子碰撞中的前向碎片。特别是，利用一种称为FMS的铅玻璃量热计研究了横向自旋依赖关系，该量能器位于恒星探测器的前方。我们的目标是描述这一结果对事件运动学的依赖。我们测试了与QCD相关的预测，即质子的自旋如何与夸克的自旋相关，以及这如何修改可观察到的截面。这笔赠款支持收集新的RHIC FMS数据并对该数据进行分析。目的是更好地理解关于质子性质的最基本的问题。质子被理解为由夸克和胶子通过强大的力结合在一起。该项目研究夸克自旋在质子结构中所起的作用。这项调查涉及布鲁克海文国家实验室恒星探测器中的FMS量热计的建造和持续运行。FMS设备对STAR中的所有其他合作者都可用。超过500名恒星合作者在不同的物理主题上工作，其中许多主题因FMS的存在而得到加强。这项研究涉及帮助制造电子产品和分析实验数据的本科生。它涉及研究生，包括那些由这笔助学金资助的人和其他使用我们设备的人。我们还向感兴趣的初中生或高中生介绍我们的工作，并尽可能让他们参与进来。

Proton high energy structure and the high energy proton-proton interaction depend on the spin and angular momentum of the underlying quarks and gluons. Unique tools are available at the Brookhaven Relativistic Heavy Ion Collider (RHIC), which make it possible to study the role of the spin of the proton constituents in polarized proton collisions. RHIC is the first high energy polarized proton collider, where experimentalists can prepare the spin orientation of high energy protons before they collide. These polarized proton collisions are studied in the STAR detector with center of mass energies up to 500 GeV. When relativistic protons collide, they produce high energy fragments including neutral pions, etas and jets of particles. It is in the very forward region where particle production is most sensitive to the orientation of the proton spin. This research involves measurement of forward fragments in relativistic proton-proton collisions. In particular, transverse spin dependence is studied using a lead-glass calorimeter called the FMS, which is located in the forward region of the STAR detector. The goal is to characterize the dependence of this production on event kinematics. We test QCD related predictions of how the spin of the proton correlates with the spin of quarks and how this can modify the observable cross sections. This grant supports the collection of new RHIC FMS data and the analysis of that data. The objective is better understanding of the most basic questions about the nature of the proton.The proton is understood to consist of quarks and gluons bound together by the strong force. This project investigates the role quark spin plays in the structure of the proton. This investigation involves the construction and ongoing operation of the FMS calorimeter in the STAR detector at Brookhaven National Lab. The FMS apparatus is available to all the other collaborators in STAR. The over 500 STAR collaborators work on a diverse range of physics topics, many of which are enhanced by the presence of the FMS. This research involves participation of undergraduate students who assist in fabrication of electronics and in analysis of data from the experiment. It involves graduate students, both those supported by this grant and others who use our apparatus. We also introduce interested middle school or high school students to our work and involve them where possible.