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arXiv 1708.03062hep-phnucl-th
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介子-介子非弹性散射的截面

Cross sections for inelastic meson-meson scattering

Kai Yang, Xiao-Ming Xu, H. J. Weber

备注：
32 pages, 6 figures, 3 tables
发表信息：
Phys. Rev. D 96, 114025 (2017)
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摘要：

我们研究了两种介子-介子非弹性散射。第一种是非弹性2- 2介子-介子散射，它受夸克交换以及夸克-反夸克湮灭和产生的控制。给出了$πK \to ρK^\ast$对$I=1/2$、$πK^\ast \to ρK$对$I=1/2$、$πK^\ast \to ρK^\ast$对$I=1/2$和$ρK \to ρK^\ast$对$I=1/2$的非极化截面公式。在阈值附近，夸克交换在临界温度附近占主导地位。第二类是2：1介子-介子散射，其过程是一个初始介子中的一个夸克和另一个初始介子中的一个反夸克湮灭为一个胶子，然后胶子被另一个反夸克或夸克吸收。导出了该过程的跃迁势。四个费曼图在树的水平上有助于2-1介子-介子散射。从$S$矩阵元出发，导出了具有跃迁振幅的同位旋平均非极化截面。$ππ\to ρ$和$πK \to K^*$的截面随温度的升高而减小。

英文摘要：

We study two kinds of inelastic meson-meson scattering. The first kind is inelastic 2-to-2 meson-meson scattering that is governed by quark interchange as well as quark-antiquark annihilation and creation. Cross-section formulas are provided to get unpolarized cross sections for $πK \to ρK^\ast$ for $I=1/2$, $πK^\ast \to ρK$ for $I=1/2$, $πK^\ast \to ρK^\ast$ for $I=1/2$, and $ρK \to ρK^\ast$ for $I=1/2$. Near threshold, quark interchange dominates the reactions near the critical temperature. The second kind is 2-to-1 meson-meson scattering with the process that a quark in an initial meson and an antiquark in another initial meson annihilate into a gluon and subsequently the gluon is absorbed by the other antiquark or quark. The transition potential for the process is derived. Four Feynman diagrams at tree level contribute to the 2-to-1 meson-meson scattering. Starting from the $S$-matrix element, the isospin-averaged unpolarized cross section with transition amplitudes is derived. The cross sections for $ππ\to ρ$ and $πK \to K^*$ decrease with increasing temperature.

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