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arXiv 1306.6823hep-phnucl-th
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高能$pp \to pp π^{0}$反应的衍射机制

Diffractive mechanisms in $pp \to pp π^{0}$ reaction at high energies

Piotr Lebiedowicz, Antoni Szczurek

摘要:

本文研究了高能质子-质子碰撞中$π^{0}$介子的唯一产生。计算中包括衍射韧致辐射(Drell-Hiida-Deck型模型)、光子-光子、光子-Ω和光子-奇子交换机制。$π^{0}$ -韧致辐射贡献在大的(向前,向后)π介子快度下占主导地位,在小的$π^0 p$不变质量下占主导地位,因此可能被误解为罗珀共振$N^{*}(1440)$。预测了mb量级的大截面。我们预测强烈的依赖性的斜率在$t$(平方四动量转移之间的进出质子)的补充激发$π^{0} p$系统的质量。在高能量和中快度时,光子-光子贡献占主导地位,但相应的截面相当小。此外,还包括光子-odderon和odderon-光子的贡献,并给出了它们的贡献的第一次估计(上限)。我们建议在中快度和$p_{\perp,π^{0}} \sim$ 0.5 GeV的odderon贡献的搜索。我们的预测已经准备好在大型强子对撞机上进行验证。这里讨论的韧致辐射机制也有助于$pp \to p(n π^{+})$反应。这两个通道都对低质量单衍射截面有相当大的贡献,必须包括在外推测得的实验单衍射截面中。

英文摘要:

We present a study of exclusive production of $π^{0}$ meson in proton-proton collisions at high energies. Both diffractive bremsstrahlung (Drell-Hiida-Deck type model), photon-photon, photon-omega and photon-odderon exchange mechanisms are included in the calculation. The $π^{0}$-bremsstrahlung contribution dominates at large (forward, backward) pion rapidities and contributes at small $π^0 p$ invariant mass and could be therefore misinterpreted as the Roper resonance $N^{*}(1440)$. Large cross sections of the order of mb are predicted. We predict strong dependence of the slope in $t$ (squared four-momentum transfer between ingoing and outgoing proton) on the mass of the supplementary excited $π^{0} p$ system. At high energy and midrapidity, the photon-photon contribution dominates over the diffractive components, however, the corresponding cross section is rather small. The photon-odderon and odderon-photon contributions are included in addition and first estimates (upper limits) of their contributions are presented. We suggest a search for the odderon contribution at midrapidity and at $p_{\perp,π^{0}} \sim$ 0.5 GeV. Our predictions are ready for verification at LHC. The bremsstrahlung mechanisms discussed here contribute also to the $pp \to p(n π^{+})$ reaction. Both channels give a sizable contribution to the low-mass single diffractive cross section and must be included in extrapolating the measured experimental single diffractive cross section.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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