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Significant enhancements of J/ψ production at very low transverse momenta were recently observed by the ALICE and STAR collaborations in peripheral hadronic A+A collisions. The anomalous excess points to coherent photon-nucleus interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. Assuming that the coherent photoproduction is the underlying mechanism responsible for the excess observed in peripheral A+A collisions, its contribution in p+p collisions with nuclear overlap, i.e. nonsingle-diffractive collisions, is of particular interest. In this paper, we perform a calculation of exclusive J/ψ photoproduction in non-single-diffractive p+p collisions at the RHIC and LHC energies based on the pQCD motivated parametrization using the world-wide experimental data, which could be further employed to improve the precision of the phenomenological calculations for photoproduction in A+A collisions. The differential rapidity and transverse momentum distributions of J/ψ from photoproduction are presented. In comparison with the J/ψ production from hadronic interactions, we find that the contribution of photoproduction is negligible. 相似文献
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基于多气隙电阻板室(MRPC)的STAR飞行时间探测器的一个板条的原型(TOFr)参加了2003年STAR实验的质子–质子对撞和氘–金对撞的物理运行.利用STAR实验中原有的赝顶点位置探测器(pVPD)和时间投影室(TPC),结合TOFr的时间及幅度信号,并考虑TOFr每个探测单元的尺寸,对影响时间分辨的各种因素进行了修正,实现了对TOFr的标定.实验数据给出的TOFr的本征时间分辨为85ps,在两倍标准方差下,其对π/K及K/p分辨的动量分别达到了1.6GeV/c和3.0GeV/c,大大提高了STAR探测器的粒子鉴别能力. 相似文献
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新时期企业创新网络中的跨组织知识共享,成为组织间知识资源有效利用的重要方式。通过构建有限理性、知识位势条件下主客体组织的跨组织知识共享演化博弈模型,研究分析了创新网络中主客体组织跨组织知识共享的策略选择。结果表明企业跨组织知识共享中的合作意愿、合作利益分配、合作双方的知识存量及知识结构差异、知识保护力度、社会联系等均是影响双方合作效率的重要因素。其中,最优的利益分配范围、主客体组织的知识存量及知识结构、知识保护力度等对企业创新网络中跨组织知识共享合作的成功起到关键性作用。 相似文献