η_c与γ协同产生与核内胶子分布

【作者】 苗文丹；

【导师】 段春贵；

【作者基本信息】 河北师范大学 ， 理论物理， 2006， 硕士

【摘要】 EMC效应反映了束缚核子结构函数与自由核子结构函数的差异,说明束缚核子内部的夸克—胶子分布与自由核子的夸克—胶子分布明显不同。在EMC效应发现后,提出许多模型从不同的观点出发,研究和探寻核子结构函数核效应的物理本质,但是这些模型都带有可调整的参数,并且拟合实验的数据点少,所用模型不能在一个统一的框架内对整个x区的核效应给出合理地解释。为克服以上缺点,K.J.Eskola等和M.Hirai等利用不依赖于物理模型的整体分析,通过拟合现有轻子—原子核深度非弹性散射以及高能质子—原子核碰撞核Drell-Yan过程实验数据,分别得到了束缚核子中的部分子分布函数。 本文使用不依赖于模型的束缚核子的胶子分布函数,在色八重态模型的框架内,研究了质子—质子,质子—原子核碰撞的η_c与γ协同产生过程。我们计算了p-Au、p-p碰撞η_c与γ协同产生过程的微分截面dσ/dp_T的比值,发现η_c与γ协同产生过程与核内束缚核子的胶子分布函数关系密切,通过对高能质子与原子核碰撞η_c与γ协同产生过程的实验研究,可以加深我们对核内胶子分布的认识。更多还原

【Abstract】 EMC effects reflect that bound nucleon structure functions are different from free nucleon. The inner structure of bound nucleon is also different from free nucleon. After the found of EMC effect, many models are used to study the nuclear effect of the nucleon structure functions. But these models have some parameters and small experimental data. So they can’t sound explain to nuclear effects in all x regions. The model-independent method given by K.J.Eskola et.al. and M.Hirai are introduced. The parton distributions function of bound nucleon are obtained through the experimental data of deep inelastic scatting and Drell-Yan process.Within the color-octet model the associate η_c+γ production inthe p-p and p-Au collisions is studied with nuclear gluon distribution function independent on models. In this paper wecalculated the cross-section ratios of associate η_c + γ productionin the p-p and p-Au collisions and found that this process is connected closely with the nuclear gluon distribution function. Bystudying the associate η_c + γ production in high energy p-Aucollision, we can know more about the nuclear gluon distribution function.更多还原