The Effect of strange Quark Spin and Higher Twist to QCD

奇异夸克自旋和高扭对QCD的影响

• 批准号: 07044076
• 负责人: HORIKAWA Naoaki
• 金额: $ 15.62万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044076/
• 关键词: SMC; spin; quark spin; nucleon spin; polarized Target; QCD; Bjorken sum rule; Ellis-Jaffe sum rule; 偏局標的; スピンクライシス; 偏極ミューオン; スピン依存構造関数

Our group has achieved this year the measurement of the spin-dependent structure function g_1 (chi) of the proton at CERN.This measurement was motivated by the behavior of g^P_ (chi, Q^2) in the small chi region below chi=0.02. In the previous measurement in 1993, it showed the tendency to increase with smaller chi. The measurement has been done from April 20 to September 17. Japanese members contributed not only in the field of polarized target operation and polarization analysis, but also in the maintenance of the MWPCs and the data acquisition by the spectrometer.The experimental conditions were following. (1) The muon beam and intensity were 190GeV and 4.5*10^7 ppp, respectively. The repitition rate of the beam was 14.4sec.. (2) The polarized target material was solid ammonia (NH_3) with a polarization of about 90% in average. By adopting NH_3 as target material, we could obtain scattering data 20-30% more than the butanol target. The acquired data are now under analysis. Mr.s Miya … More chi and Ogawa are involved in this job.By adding the present data to those obtained in 1993, we can get more reliable values of g^P_ (chi, Q^2) in the lower chi region. It makes possible to give the decisive conclusion on the quark spin contribution to nucleon spin and to test the Bjorken sum rule and Ellis-Jaffe sum rule more precisely.In parallel with the data acquisition, our group members progressed the data analysis for the 1995 deuteron target experiment. Especially, Mr.Ogawa worked as a key person of the analysis in SMC group. By making many kinds of checks, like detector position, false asymmetry, radiative corrections, QCD evolutions to the asymmetry parameter A^d_ and g^d_ (chi, Q^2), etc., he deduced the final g^d_ (chi, Q^2) valuse to 1995 deuteron data. He has summarized the 1995 experiment for the deuteron and reported at the International Symposium on High Energy Spin Physics held in Amsterdam on Sep. 4-10,1996. He has summarized this to Doctor Thesis and proposed to Department of physics, Nagoya University in January, 1997. He was given The Ph.D in March, 1997.Dr.Iwata discussed with JINR (DUBNA) people on the possibility of the new polarized target material and the polarization experiment at DUBNA to investigate the quark structure in nucleus, using the polarized deuteron beam at DUBNA. Less

我们的研究小组今年在CERN完成了质子自旋相关结构函数g_1（chi）的测量，这一测量的动机是g^P_（chi，Q^2）在chi=0.02以下的小chi区域的行为。在1993年的上一次测量中，它显示出随着较小的chi而增加的趋势。测量时间为4月20日至9月17日。日本成员不仅在偏振目标操作和偏振分析领域做出了贡献，而且在MWPC的维护和光谱仪的数据采集方面也做出了贡献。(1)μ子的能量和强度分别为190 GeV和4.5*10^7 ppp。束流重复率为14.4秒。(2)极化靶材料为固体氨（NH_3），平均极化率约为90%。采用NH_3作靶材料，可获得比丁醇靶高20-30%的散射数据。目前正在分析所获得的数据。宫先生 ...更多信息 chi和Ogawa等人参与了这项工作，将现有资料与1993年的资料相加，可以得到较可靠的低chi区g^P_（chi，Q^2）值。这使得我们能够给出夸克自旋对核子自旋贡献的决定性结论，并更精确地检验Bjorken和规则和Ellis-Jaffe和规则。特别是小川先生在SMC集团担任分析的关键人物。通过对探测器位置、假非对称性、辐射修正、QCD演化对非对称性参数A^d_和g^d_（chi，Q^2）等的检验，他用1995年的氘核数据推导出了最终的g^d_（chi，Q^2）值。他总结了1995年的氘核实验，并在1996年9月4- 10日在阿姆斯特丹举行的高能自旋物理国际研讨会上作了报告。1997年1月，他将此总结为博士论文并向名古屋大学物理系提出。1997年3月获得博士学位。1997年3月，岩田博士与日本原子核研究所（杜布纳）的人员讨论了利用杜布纳的极化氘束研究核中夸克结构的新极化靶材料和极化实验的可能性。少

项目成果

N.Horikawa and SMC: "The spin dependent structure function g_1 (chi) of the deuteron from deep-inelastic muon scattering" Phys.Lett.B.

N.Horikawa 和 SMC：“来自深非弹性 μ 子散射的氘核的自旋相关结构函数 g_1 (chi)” Phys.Lett.B。

N.Horikawa and SMC: "Large enhancement of deuteron polarization with frequency modulated microwaves" Nucl.Instr.and Meth.in Phys.Research. A3728. 339-343 (1996)

N.Horikawa 和 SMC：“利用调频微波大幅增强氘核极化”Nucl.Instr.and Meth.in Phys.Research。

Y.Miyachi et al.: "The development of the polyethylene polarized target" Genshikaku kenkyu.

Y.Miyachi 等：“聚乙烯极化靶材的开发”Genshikaku kenkyu。