标题： 矢量介子产生中的硬扩散在HERA 显示英文标题

标题： The Hard Diffraction in Vector Meson Production at HERA

摘要： 在微扰QCD框架下给出了HERA上弹性矢量介子产生的结果。 研究了J/Psi光致产生产率和rho电致产生产率的截面能量依赖性。 对于rho电致产生产率，给出了完整的极化分析，包括自旋密度矩阵的15个元素的测量以及R=sigma_L/sigma_T的测量。 最后讨论了更重的矢量介子（Psi'和Upsilon）的产生。 显示英文摘要

摘要： Results on elastic vector meson production at HERA are presented in the framework of perturbative QCD. The energy dependence of the cross section for J/Psi photoproduction and for rho electroproduction is studied. A full polarisation analysis, including the measurement of the 15 elements of the spin density matrix and of R=sigma_L/sigma_T, is presented for rho electroproduction. Finally heavier vector mesons (Psi' and Upsilon) production is discussed.