横向电荷分布作为核子横动量的探测器
Transverse Charge Distribution as a Probe of Nucleon Transversity
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中文总结 AI 辅助
研究提出将横向电荷分布作为自旋敏感电荷流探测器用于核子层析成像，推导其算符乘积展开，应用于RHIC上的横向极化\(p^\uparrow p\)碰撞，可抑制背景、增强不对称性，为提取横动量提供清晰精确途径。
中文摘要 AI 辅助
我们引入横向电荷分布作为用于碎裂和核子层析成像的自旋敏感电荷流探测器。通过测量碎裂夸克周围净电荷的角分布，此可观测量完全依赖于带电粒子方向和电荷符号的追踪，严格避免了量热能量测量的需求。在领头扭转下，分布分解为非极化电荷单极子和手征奇异横向电荷偶极子。我们推导了这些分布到电荷加权共线矩的算符乘积展开：单极子由电荷守恒确定，而偶极子由柯林斯效应控制并直接与横动量耦合。将此形式主义应用于相对论重离子对撞机（RHIC）上的横向极化\(p^\uparrow p\)碰撞，我们表明电荷加权抑制了非极化单极子背景，并使来自带相反电荷强子的自旋相关偶极子相干相加。这种相干强烈增强了产生的方位角不对称性，为提取横动量建立了一条理论上清晰且实验上精确的仅基于轨道的途径。
英文摘要
We introduce the transverse charge distribution as a spin-sensitive charge-flow probe for fragmentation and nucleon tomography. By measuring the angular distribution of net electric charge around a fragmenting quark, this observable relies entirely on the tracking of charged-particle directions and charge signs, strictly bypassing the need for calorimetric energy measurements. At leading twist, the distribution decomposes into an unpolarized charge monopole and a chiral-odd transverse charge dipole. We derive the operator product expansion of these distributions onto charge-weighted collinear moments: a charge monopole and a charge dipole governed by the Collins effect and couples directly to transversity. Applying this formalism to transversely polarized $p^\uparrow p$ collisions at RHIC, we show that charge weighting suppresses the unpolarized monopole background and causes the spin-dependent dipoles from oppositely charged hadrons to add coherently. This coherence strongly enhances the resulting azimuthal asymmetries, establishing a theoretically clean and experimentally precise track-only avenue for extracting transversity.
