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arXiv 0906.0286nucl-thhep-ph
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在GSI反质子和离子研究设施(GSI-FAIR)和日本质子加速器研究综合体(J-PARC)可获得的能量范围内的独家标量$f_0(1500)$介子生产

Exclusive scalar $f_0(1500)$ meson production for energy ranges available at the GSI Facility for Antiproton and Ion Research (GSI-FAIR) and at the Japan Proton Accelerator Research Complex (J-PARC)

Antoni Szczurek, Piotr Lebiedowicz

摘要:

我们计算了$p \bar p \to N_1 N_2 f_0$(FAIR@GSI)和$p p \to p p f_0$(J-PARC@Tokai)的纯量$f_0(1500)$介子(胶球候选者)产生的微分分布。首次计算了QCD衍射、π介子-π介子交换流(MEC)分量以及具有中间π介子环的双衍射机制。可以可靠地计算的π介子-π介子分量在接近阈值时占主导地位,而衍射分量可能仅在较大能量时才占主导地位。目前只能得到QCD衍射分量的上限。衍射分量的计算是基于双胶子影响因子以及Khoze-Martin-Ryskin方法的框架下提出的衍射希格斯玻色子玻色子的生产。不同的未积分胶子分布函数(UGDFs)从文献中使用。相当大的截面,由于π介子融合的PANDA能量,胶子机制被证明是可以忽略不计的预测。接近阈值的$f_0(1500)$的产生会限制所谓的$πNN$形状因子在更大的π虚拟区域。我们详细讨论了产生$f_0(1500)$介子的两π介子背景。我们将我们的结果与WA 102合作组织的现有数据进行了比较。

英文摘要:

We evaluate differential distributions for exclusive scalar $f_0(1500)$ meson (glueball candidate) production for $p \bar p \to N_1 N_2 f_0$ (FAIR@GSI) and $p p \to p p f_0$ (J-PARC@Tokai). Both QCD diffractive, pion-pion meson exchange current (MEC) components as well as double-diffractive mechanism with intermediate pionic loop are calculated for the first time in the literature. The pion-pion component, which can be reliably calculated, dominates close to the threshold while the diffractive component may take over only for larger energies. At the moment only upper limit for the QCD-diffractive component can be obtained. The diffractive component is calculated based on two-gluon impact factors as well as in the framework of Khoze-Martin-Ryskin approach proposed for diffractive Higgs boson production. Different unintegrated gluon distribution functions (UGDFs) from the literature are used. Rather large cross sections due to pion-pion fusion are predicted for PANDA energies, where the gluonic mechanism is shown to be negligible. The production of $f_0(1500)$ close to threshold could limit the so-called $πNN$ form factor in the region of larger pion virtualities. We discuss in detail the two-pion background to the production of the $f_0(1500)$ meson. We compare our result with the existing data of %the WA102 Collaboration.

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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