The handbag contribution to γγ→ππ and KK
The handbag contribution to γγ→ππ and KK
复制标题
手袋对γγ→ππ和KK的贡献
DOI：
10.1016/s0370-2693(02)01489-2
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发表时间：
2001
影响因子：
4.4
通讯作者：
C. Vogt
中科院分区：
文献类型：
--
作者：
M. Diehl;P. Kroll;C. Vogt
我们研究了在大的能量和动量转移下，软手袋对双光子湮灭成π介子或K介子对的贡献。振幅表示为一个硬γγ→q q <$$>子过程乘以一个形状因子，该形状因子描述了从q q <$到介子对的软跃迁。我们发现计算出的角度依赖的横截面与数据吻合良好，并提取湮灭形状因子的合理大小。手提袋机制的一个关键预测是，带电和中性π介子对的微分截面是相同的，与硬散射方法中发现的形成鲜明对比。
We investigate the soft handbag contribution to two-photon annihilation into pion or kaon pairs at large energy and momentum transfer. The amplitude is expressed as a hard γγ→q q ̄ subprocess times a form factor describing the soft transition from q q ̄ to the meson pair. We find the calculated angular dependence of the cross section in good agreement with data, and extract annihilation form factors of plausible size. A key prediction of the handbag mechanism is that the differential cross section is the same for charged and neutral pion pairs, in striking contrast with what is found in the hard scattering approach.