质子的自旋危机问题  

Hhe Spin Crisis of the Proton

作　　者：马维兴[1] 武青[2] 

机构地区：[1]中国科学院高能物理研究所 [2]国防科技大学物理系

出　　处：《高能物理与核物理》1997年第4期362-367,共6页High Energy Physics and Nuclear Physics

摘　　要：建立了质子自旋依赖的结构函数的第一矩与ＧＤＨ求和规则之间的关系．根据这个求和规则和重子结构的［ＳＵｓｆ（６）Ｏ（３）］ＳＵｃ（３）夸克模型，讨论了质子的自旋问题，并把理论的结果与ＥＭＣ和ＳＬＡＣ的实验作了比较，结果相一致．发现在低动量转移区，Ｐ３３（１２３２）的光激发的贡献是最重要的，而且是负的．在高动量转移区，Ｐ３３的贡献是正的，而且随Ｑ２的增加很快减小，可以略去，从负值到正值的转折点是在Ｑ２＝０．The relationship between the Gerasimov Drell Hearn (GDH)sum rule and the first monent,Γ P the proton spin dependent structure function integral,is established.According to the sum rule and quark structure model of baryon,[SU sf (6)O(3)]SU c (3),the spin problem of the proton is discussed The present theoretical results are also compared with the data measured by EMC and SLAC groups.Our prediction is in good agreement with the data.We find that the P 33 (1232)photo cxcitation dominates the spin structure function integrals and contributes negatively at low momentum transfer.At higher momentum transfer,the contribution of the P 33 is positive,and it decreases rapidly as Q 2 increasing and finally becomes negligible The integral changes its sign from negative into positive at about Q 2=0.3 GeV 2

关 键 词：质子自旋 自旋物理 虚光子吸收 原子物理 

分 类 号：O562.2[理学—原子与分子物理]