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运用微扰QCD讨论了重离子碰撞中大横动量轻子对的分布, 计算了Au-Au碰撞中两个部分子产生的轻子对的贡献。引入了轻子对产生的直接单光子过程和分解单光子过程。大横动量情况下的所有过程都包括在内, 而且考虑了核遮蔽效应和同位旋效应, 作为QGP背景的双轻子信号有了一个好的修正。The large transverse momentum distribution of lepton pairs produced in heavy-ion collisions has been studied, making use of the perturbative QCD. The contribution of the two parton production process into lepton pairs in Au Au collisions is calculated. Lepton pair production with the direct single photon process and the resolved single photon process are introduced. We believe that the photon processes are significant. The complete processes at large transverse momentum are included, and moreover, the effect of shadowing and isospin of nucleus are also considered in heavy ion collisions. Dilepton signals to regard the background of QGP have a good correction. 相似文献
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计算了由准相干双光子相互作用导致的低横动量双轻子产生。 对于不同的质量范围, 准相干双光子相互作用在低横动量区域都很重要。 将计算结果与相对论重离子对撞机RHIC的PHENIX实验数据进行比较, 发现随着双轻子不变质量的增加, 准相干双光子过程的修正作用会更加明显。 相似文献
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Intermediate Mass Dileptons from the Passage of Jets and High Energy Photons through Quark-Gluon Plasma 下载免费PDF全文
The production of the intermediate mass dileptons originating from the annihilation and Compton scattering of the jets and high energy photons (resolved photons) passing through the quark-gluon plasma is calculated. The contribution of the dilepton yield due to the jet-plasma and high energy photon-plasma interaction is pronounced compared to the thermal and Drell-Yan dilepton spectrum at intermediate mass. The ordinary spectrum of thermal and Drell-Yan processes is enhanced by the jet and photon-plasma mechanism. The numerical results match to the PHENIX data accurately in the intermediate mass region for Au-Au 200 GeV/A collisions at RHIC. 相似文献
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本文基于密度泛函理论(DFT)的第一性原理平面波超软赝势方法计算了z-BC2N和z-B2CN的4种晶体结构的电子结构、硬度和光学性质。结果表明,z-BC2N(2)为直接带隙半导体,其禁带宽度2.449 eV,z-BC2N(1)为间接宽带隙半导体,其禁带宽度为3.381 eV,而z-B2CN(1)和z-B2CN(2)为导体;硬度结果显示z-BC2N(1)、z-BC2N(2)和z-B2CN(1)为超硬材料。最后通过计算z-BC2N基本光学函数与光子能量的关系表征了其光学性质。分析结果表明,z-BC2N结构可以用作良好的耐磨材料和窗口耐热材料。 相似文献
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We calculate the production of prompt and thermal photons which includes the contribution of gluons in relativistic heavy ion collisions with the equilibrium and non-equilibrium quark-gluon plasma. We develop a new thermal jet-photon conversion mechanism which plays a vital role in the low transverse momentum region. The effect of the non-equilibrium quark-gluon plasma enhances the contribution of the thermal photons. The shadowing and iso-spin of the nucleus which can properly estimate the prompt photon production are also considered in our calculation. 相似文献
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提出了一种夸克 胶子等离子体中的喷注 光子转换机制。 对于热光子而言, 在热夸克 胶子媒介中的喷注 光子转换是一个非常重要的热光子来源。 喷注可以通过次级康普顿散射和湮灭过程来实现喷注 光子转换。 此外, 还考虑了在快光子产生过程中起重要修正作用的胶子 光子贡献, 其中,核遮蔽效应和同位旋效应也被引入到了部分子模型中。We develop a jet photon conversion mechanism in the expanding quark gluon plasma. The jet photon conversion in hot quark gluon medium is a vital source of the thermal photon production. The jet converts into photons via the secondary Compton and annihilation processes in the quark gluon plasma. The gluon photons are also considered in the calculation of prompt photons which includes the effect of the shadowing and isospin of nucleus. We find that the prompt gluon photons are also an important modification to prompt photons. 相似文献
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We consider the production sources of prompt and thermal photons which include the contribution of gluons in relativistic heavy ion collisions. Considering in our calculation the shadowing and iso-spin effects of the nucleus we can properly estimate the prompt photon production. We develop a new thermal jet-photon conversion mechanism which plays a vital role in the low transverse momentum region. The effect of the non-equilibrium quark-gluon plasma enhances the contribution of thermal photons. 相似文献