arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.01923hep-phnucl-exnucl-th
收藏

核子和氘靶的衍射双介子电产生

Diffractive two-meson electroproduction with a nucleon and deuteron target

W. Cosyn, B. Pire, L. Szymanowski

摘要:

两个被大快度间隙隔开的介子的衍射电或光产生以非常特定的方式提供了对广义部分子分布(GPD)的访问。首先,这些反应允许通过选择所产生的矢量介子之一进行横向极化来容易地访问手征奇横观夸克GPD。其次,它们只对所谓的ERBL区域敏感,在该区域GPD不受前向夸克分布的限制。第三,偏度参数$ξ$与Bjorken $x_\text{Bj}$变量无关,而是与快度间隙的大小有关。我们分析了不同的渠道($ρ_L^0\,ρ_{L/T}, ρ^0_L\,ω_{L/T}$和$ρ^0_L\,π$生产)的核子和氘核的目标。在运动学域中进行分析,其中从光子到衍射产生的矢量介子的大动量转移引入了硬尺度(交换的硬Pomeron的虚拟性)。这使得强子部分的过程中的GPD的共线因式分解的框架内的描述。我们发现,非极化截面很大程度上依赖于核子的手征偶夸克和手征奇夸克分布的参数化,以及介子分布振幅的形状。的速率被证明是在未来的电子-离子对撞机的能力范围内。

英文摘要:

The diffractive electro- or photo-production of two mesons separated by a large rapidity gap gives access to generalized parton distributions (GPDs) in a very specific way. First, these reactions allow to easily access the chiral-odd transversity quark GPDs by selecting one of the produced vector meson to be transversely polarized. Second, they are only sensitive to the so-called ERBL region where GPDs are not much constrained by forward quark distributions. Third, the skewness parameter $ξ$ is not related to the Bjorken $x_\text{Bj}$ variable, but to the size of the rapidity gap. We analyze different channels ($ρ_L^0\,ρ_{L/T}, ρ^0_L\,ω_{L/T}$ and $ρ^0_L\,π$ production) on nucleon and deuteron targets. The analysis is performed in the kinematical domain where a large momentum transfer from the photon to the diffractively produced vector meson introduces a hard scale (the virtuality of the exchanged hard Pomeron). This enables the description of the hadronic part of the process in the framework of collinear factorization of GPDs. We show that the unpolarized cross sections depend very much on the parameterizations of both chiral-even and chiral-odd quark distributions of the nucleon, as well as on the shape of the meson distribution amplitudes. The rates are shown to be in the range of the capacities of a future electron-ion collider.

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。

↑