γ-p碰撞中J/ψ的硬衍射产生

J/ψ Production in Hard Diffractive γ-p Collision

按着重夸克偶素产生的NRQCD因子化方案 ,计入q q的色八重态产生机制 ,采用L .Alvero等给出的三组Pomeron的部分子分布函数 ,在s =2 0 0GeV ,4GeV <pT<1 0GeV条件下计算并讨论了γ + p→p +J/ ψ +X过程中J/ ψ的产生截面 .该截面的大小受NRQCD的长程矩阵元的影响很大 ,但该截面与单举截面的比值很少受这种影响 .如果能消除长程矩阵元的影响 ,则该比值的大小只与Pomeron的流因子及部分子分布函数有关 .

In the frame of color octet mechanism and according to NRQCD factorization of q production,using three sets of parton distribution function of Pomeron given by L.ALvero et al.,the cross section of J/ψ in γ+p→p+J/ψ+X process is calculated and discussed with the s =200GeV,4GeV< p T<10GeV. Our results show that the NRQCD matrix elements had a great influence on cross sections,but a little influence on the ratio of diffractive cross section to inclusive cross section. If the influence is eliminated,the ratio is only related to the flux factor and parton distribution functions of Pomeron.