Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
复制标题
前角离核的赝标量介子的不相干光产生
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
M. Khandaker
中科院分区：
文献类型：
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作者：
S. Gevorkyan;A. Gasparian;L. Gan;I. Larin;M. Khandaker
光子标记装置的最新进展以及新型的高分辨率快速量热法使我们能够以百分之一级的精度测量赝标介子在原子核上的光生截面。辐射衰变宽度的提取，需要测试对称性破缺效应的QCD，从这些测量在小角度是由Primakoff方法。这种方法需要在理论上处理所有参与这些反应的过程，使它们处于相同的百分比水平。在我们的前一篇论文中，对包括核相干振幅在内的一般过程进行了最新的描述。在Glauber多重散射理论的框架下，考虑到介子在核中的吸收和在前向产生角下的Pauli抑制，我们得到了赝标介子离核光生的非相干截面的解析表达式.作为对所得公式的说明，我们计算了闭合壳层核^16 O和非闭合壳层核^12 C光生的非相干截面。这些计算允许一个比较不同的方法，并估计其对所考虑的过程的非相干截面的影响。
Recent advances in the photon tagging facilities together with the novel, high-resolution fast calorimetry make it possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, in the framework of the Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and the Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoherent cross section for photoproduction from a closed shell nucleus, ^16O, and from an unclosed shell nucleus, ^12C. These calculations allow one to compare different approaches and estimate their impact on the incoherent cross section of the processes under consideration.