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Study of the Spin Structure of the Nucleon with W production in polarized pp collisions

极化 pp 碰撞中产生 W 的核子自旋结构研究

基本信息

批准号：
16340072
负责人：
SAITO Naohito
金额：
$ 10.43万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

W production in polarized pp collisions is expected to play an important role in investigation of anti-quark distribution in the proton, since its production is dominated by quark-anti-quark scattering. Indeed, W+ should be produced from left handed up quark and right handed anti-down quark. Therefore W production in pp collision is one the best tools to study the spin flavor structure of the proton.At the Relativistic Heavy Ion Colliser (RHIC) at Brookhaven National Laboratory can accelerate spin polarized proton beams up to 250 GeV and collide them to produce W boson copiously. Production of W can be identified with the detection of high momentum muon. To realize such measurement at PHENIX experiment, we should provide an additional capability to trigger data acquisition system by selecting the high momentum muon candidates. In this research program, we have developed the electronics board to provide a hit information from Muon Tracking Detector into the trigger decision algorithm. The newly developed electronics board steals about 10% of the pulse from the Muon Tracking Detector and amplifies to be discriminated with a given threshold. Such hit information will be processed in the Field Programmable Gate Arrays to select high momentum tracks, i.e. almost straight tracks at online level. This addition of the new electronics certainly increase the noise level in the existing read out system, and we need to minimize such effects. Within this research program, we have developed the electronics board with an optimal performance, and demonstrated that the increase in the noise level is fully acceptable with the real Muon Tracking Detectors.Consequently we are now ready for the production of the new electronics system to realize the momentum selective muon trigger. For PHENIX experiment.

极化pp碰撞中的W产生是由夸克-反夸克散射决定的，因此在研究质子中的反夸克分布方面将发挥重要作用。事实上，W+应该是由左手上夸克和右手反下夸克产生的。在布鲁克海文国家实验室（Brookhaven National Laboratory）的相对论重离子对撞机（RHIC）上，可以将质子束加速到250 GeV，并使它们碰撞产生大量的W玻色子。W的产生可以通过对高动量μ子的探测来确定。为了在PHENIX实验中实现这种测量，我们应该通过选择高动量μ子候选者来提供额外的触发数据采集系统的能力。在本研究计划中，我们开发了电子板，以提供从μ子跟踪探测器到触发决策算法的命中信息。新开发的电子板从μ子跟踪探测器中窃取了大约10%的脉冲，并将其放大到给定的阈值。这种命中信息将在现场可编程门阵列中处理，以选择高动量轨道，即在线水平的几乎直的轨道。这种新的电子设备的增加肯定会增加现有读出系统中的噪声水平，我们需要将这种影响降至最低。在本研究计划中，我们已经研制出了性能最佳的电子学板，并证明了真实的μ子跟踪探测器的噪声水平的增加是完全可以接受的，因此我们现在已经准备好生产新的电子学系统，以实现动量选择μ子触发。凤凰实验。