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We investigate the nuclear shadowing effect on the K factor in the Drell-Yan process by introducing a Shadowing factor into the corresponding quantum chromodynamical αs order corrections.K factors for Au-Au collisions are calculated at the centre-of-mass system energies √s=60,130 and 200 GeV while the nuclear shadowing factor is taken into account.The numerical results indicate that the nuclear shadowing factor obviously raises the K value in the small x region,and for the same nucleon the K valus becomes smaller as the energy increases.The nuclear shadowing effect could be one reason for creating the non-constancy of the K factor. 相似文献
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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. 相似文献
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在不同能量下, 利用核束缚能对虚光子四动量的平方项进行修正, 分别计算了Sn核碰撞中核束缚能对反应截面中湮灭项和康普顿散射项及K因子的影响。 结果表明, 核束缚能在小x区域对反应截面中湮灭项和康普顿散射项及K因子的影响明显, 并且能量越低这种影响越显著, 随着x2增大影响逐渐消失。 We made a revision of square of virtual photon four momentum by means of using nuclear bin ding energy formula in different energy, and we also made an accurate calculation for the effect of nuclear binding energy on K factor and Compton term and annihilate term in the Drell Yan process of the Sn Sn collision. The outcome indicates that the effect of nuclear binding energy on the annihilate term and the Compton term is marked in little x region and the effect will become more obvious with decrease of the energy and come to disappear with increase of the x. 相似文献
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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. 相似文献
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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. 相似文献