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）上有独特的工具，可以研究质子成分自旋在极化质子碰撞中的作用。RHIC是世界上第一台高能极化质子对撞机，实验人员可以在高能质子碰撞前准备其自旋方向。这些极化质子碰撞在质心能量高达500 GeV的STAR探测器上进行了研究。当相对论性质子碰撞时，它们会产生高能碎片，包括中性介子、etas和粒子喷流。它是在非常向前的区域，粒子产生对质子自旋的方向最敏感。这项研究涉及到相对论质子-质子碰撞中向前碎片的测量。特别是，横向自旋依赖研究使用铅玻璃量热计称为FMS，它位于星探测器的前部区域。我们的目标是描述这种生产对事件运动学的依赖性。我们测试了量子cd相关的预测，即质子的自旋如何与夸克的自旋相关，以及这如何改变可观察到的横截面。这项拨款支持收集新的RHIC FMS数据并对数据进行分析。目的是更好地理解关于质子性质的最基本问题。质子被认为是由夸克和胶子组成的，它们被强作用力结合在一起。这个项目研究了夸克自旋在质子结构中的作用。本研究涉及布鲁克海文国家实验室STAR探测器中FMS量热计的构建和持续运行。FMS设备可供STAR的所有其他合作者使用。500多名STAR合作者致力于各种各样的物理主题，其中许多都因FMS的存在而得到加强。这项研究需要本科生的参与，他们协助制作电子产品并分析实验数据。它涉及到研究生，既包括那些由这笔拨款支持的学生，也包括使用我们设备的其他学生。我们也会介绍感兴趣的中学生或高中生参与我们的工作，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.