高能p-A碰撞Drell-Yan过程中的初态核效应

核遮蔽和能量损失效应是p-A碰撞中两种重要的初态核效应. 本文利用从轻子-原子核深度非弹性散射实验数据中抽取的束缚核子的部分子分布函数, 在色弦模型中研究了Drell-Yan双轻子对产生过程中的能量损失效应. 通过对FNAL E772和E866实验数据的χ²分析, 得到夸克在冷核中的能量损失率为－dE/dz=2.06GeV/fm. 这和该模型理论预言的结果(－dE/dz～2GeV/fm)一致. 通过将理论计算结果与实验数据进行比较, 发现考虑到能量损失后能很好的解释实验现象.     

J/ψ-N center of mass energy dependence of nuclear absorption effect on J/ψ production

In this paper, the J/ψ nuclear absorption effect is studied at RHIC and LHC energies with the EKS98 shadowing parameterizations. By assuming that the J/ψ absorption cross section, σ abs , increases with the charmonium-nucleon （J/ψ-N） center of mass energy, s J/ψN , it is found that σ abs should depend on x F （or y） at a certain center of mass energy per nucleon pair,s , especially at LHC energies. The theoretical results with the x F （or y）-dependence of the absorption effect are in good agreement with the experiment data from PHENIX in d-Au collisions and the predicted results will be examined by the forthcoming experimental data from LHC in d-Pb collisions. Finally, we also present baseline calculations of cold nuclear matter effects on J/ψ production in nucleus-nucleus （A-A） collisions and find that the x F （or y）-dependence of absorption effect is very small at both RHIC and LHC energies in A-A collisions.     

Influence of the Nucleon Hard Partons Distribution on J/φ Suppression in a GMC Framework

In a Glauber Monte Carlo framework, taking into account the transverse spatial distribution of hard partons in the nudeon, we analyze the nuclear modification factor RdAu for J/φ in d＋Au collisions with EPS09 shadowing parametrization. After the influence of nucleon hard partons distribution is considered, a clearly upward correction is revealed for the dependence of RdAu on Neon in peripheral d＋Au collisions, however, an unconspicuous correction is shown for the results versus PT. The theoretical results are in good agreement with the experimental data from PHENIX.     

SU(6)破缺效应对核子形状因子的贡献

最近杰斐逊实验室测量了中子的两个弹性电磁形状因子之比GEn/GMn,它反映了中子内部的电磁分布并能帮助理解中子的内部结构.传统的相对论组分夸克模型在解释质子的两种电磁形状因子之比GEp/GMp是很成功的,但在解释中子的该比值时计算值比实验值要低.为了解释这种现象,我们在相对论组分夸克模型框架下计算考察了SU(6)破缺效应的贡献.发现考虑该破缺效应后的计算结果同实验符合有明显改善.     

LHC能量下D介子的核修正因子

高能质子-质子(p-p)和质子-原子核(p-A)碰撞过程中产生的D介子是分析碰撞后生成的饱和胶子性质的重要途经。考虑领头阶下的强耦合效应,在色玻璃凝聚理论(CGC)框架下研究了LHC(Large Hadron Collider, LHC)能量下p-p(p-A)碰撞过程中的D介子产生。采用由KLR-AdS/CFT色偶极模型通过傅里叶变换得到的偶极关联因子,同时利用Glauber模型考虑冷核物质效应,计算了质心能量为5.02 TeV时质子-铅核(p-Pb)碰撞中不同碰撞中心度下D介子的产生截面,并在此基础上研究了p-Pb碰撞中D介子产生及其半轻子衰变过程中的核修正因子。通过与大型强子对撞机(LHC)实验结果比较发现:考虑强耦合效应后的理论结果与ALICE和LHCb合作组的最新实验数据符合得更好。最后,本文对LHC碰撞质心能量为8.16 TeV时p-Pb碰撞中D介子产生的核修正因子给出了理论预言, 结果显示此能量下核修正因子理论值比5.02 TeV时略大。     

分布光度测量系统的消杂技术及寻优算法

采用几何光学分析法,对影响光度测量的杂散光进行分析;根据杂散光反射传输的特点,结合近似绝对黑体结构理论和吸光度加和理论,设计了具有高折反效果的凹型窄光阑阵列消杂模型,提高了对杂散光的抑制能力;由于此结构在不同光阑间隔下的消光效果不同,设计了自适应惯性权重粒子群算法来搜索光阑阵列的最优间隔,以进一步提高光阑阵列的性能.在此基础上,通过仿真和实验验证了基于最优消杂模型构建的分布光度测量系统,其测量误差与消杂之前相比由10%以上降低到了1%以下;满足相应的国际及国家标准对光源测量的误差要求,可作为现有环境下进一步抑制环境杂散光的有效手段.     

色八重态对高能π–p碰撞过程的贡献

利用QQ色八重态产生机制,计算并讨论了色八重态对高能π–p碰撞过程的贡献.发现,在大PT时,色八重态的贡献不可忽略,甚至超过色单态的贡献.计算结果与未来实验比较,可以检验色八重态产生机制及π介子中的胶子分布函数.     

阳离子树脂催化合成古龙酸甲酯的动力学研究

古龙酸甲酯化反应是生产维生素C的一个重要中间过程,目前工业上主要采用古龙酸和甲醇为原料,以浓硫酸作催化剂催化酯化.这一反应存在副反应较多,甲酯的色泽深,质量差,后续反应中需用碱进行中和等缺点,给后续处理带来困难.     

Gluon saturation and net-proton spectra in relativistic nucleus-nucleus collisions

By means of the AKK08 fragmentation function, the net-proton transverse momentum (pT) spectra in A+A collisions are studied with two phenomenological models based on the Color Glass Condensate formalism. After a χ² analysis of the experimental data from BRAHMS, the normalization constant C is extracted at RHIC energies of √sNN=62.4 and 200 GeV, and the theoretical results of the net-proton pT spectra at selected rapidities are also given. It is shown that the theoretical results are in good agreement with the experimental data. Finally, assuming the constant C should have an exponent dependence of √sNN, we also predict the theoretical results of net-proton pT spectra at LHC energies of √sNN=2.76, 3.94, and 5.52 TeV.