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首次测量了硬质排他性 π^{-}Δ^{++} 电子产生的光束-旋转不对称性,离出质子

S Diehl^1,2, N Trotta¹, K Joo¹

¹University of Connecticut, Storrs, Connecticut 06269, USA.

Physical review letters

|July 28, 2023

概括

这项研究报告了首次测量在深无弹性散射中特定粒子相互作用的结果. 结果提供了对d夸克的新见解.

科学领域:

核物理核物理核物理
粒子物理学粒子物理学
量子色态动力学量子色态动力学

背景情况:

硬专用电生成提供了一个进入核子结构的窗口.
了解d夸克对核子结构的贡献至关重要.
一般化的帕顿分布 (GPD) 提供了一个研究核子结构的框架.

研究的目的:

为了提取极化截面比 σ_{LT^{'}}/σ_{0} 对于硬专用 π^{-}Δ^{++} 电力生产.
为了探测核子中的d夸克含量.
为了访问p→Δ^{++}过渡的通用派顿分布 (GPDs).

主要方法:

利用光束-旋转不对称度的测量,使用10.2 GeV/10.6 GeV的发生电子束.
在杰斐逊实验室使用了CLAS12光谱仪.
专注于在价值体制中的前向 pion 动力学,光子虚拟性从 1.5 GeV2 到 7 GeV2.

主要成果:

在深不可弹性状态下,第一次观察硬排他性π^{-}Δ^{++}电生成.
提取了极化截面比 σ_{LT^{'}}/σ_{0}.
与π^{+}n和π^{0}p电生成的比较揭示了激发机制对不对称性的影响.

结论:

这项研究为核子中的d夸克含量提供了新的机会.
结果提供了对p→Δ^{++}过渡GPDs的见解.
激发机制显著影响观察到的不对称性.

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