Background] DIS on the polarized deuteron with detection of a proton in the nuclear breakup region (spectator tagging) represents a unique method for extracting the neutron spin structure functions and studying nuclear modifications. The tagged proton momentum controls the nuclear configuration during the DIS process and enables a differential analysis of nuclear effects. Such measurements could be performed with the future electron-ion collider (EIC) and forward proton detectors if deuteron beam polarization could be achieved. [Purpose] Develop theoretical framework for polarized deuteron DIS with spectator tagging. Formulate procedures for neutron spin structure extraction. [Methods] A covariant spin density matrix formalism is used to describe general deuteron polarization in collider experiments (vector/tensor, pure/mixed). Light-front (LF) quantum mechanics is employed to factorize nuclear and nucleonic structure in the DIS process. A 4-dimensional representation of LF spin structure is used to construct the polarized deuteron LF wave function and efficiently evaluate the spin sums. Free neutron structure is extracted using the impulse approximation and analyticity in the tagged proton momentum (pole extrapolation). [Results] General expressions of the polarized tagged DIS observables in collider experiments. Analytic and numerical study of the polarized deuteron LF spectral function and nucleon momentum distributions. Practical procedures for neutron spin structure extraction from the tagged deuteron spin asymmetries. [Conclusions] Spectator tagging provides new tools for precise neutron spin structure measurements. D-wave depolarization and nuclear binding effects can be eliminated through the tagged proton momentum dependence. The methods can be extended to tensor-polarized observables, spin-orbit effects, and diffractive processes.

中文翻译：

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带有旁观者-核子标记的极化电子-氘核深层非弹性散射

背景技术极化氘核上的DIS（具有检测核分裂区中的质子）（旁观者标记）代表了一种提取中子自旋结构功能并研究核修饰的独特方法。标记的质子动量可控制DIS过程中的核构型，并能够对核效应进行差异分析。如果可以实现氘核电子束极化，则可以使用未来的电子离子对撞机（EIC）和前向质子探测器进行此类测量。［目的］建立带有观众标记的极化氘氘DIS的理论框架。制定中子自旋结构提取程序。[方法]使用协变自旋密度矩阵形式来描述对撞机实验中的一般氘核极化（矢量/张量，纯/混合）。光前（LF）量子力学被用来分解DIS过程中的核和核子结构。LF自旋结构的4维表示用于构造极化氘核LF波函数并有效评估自旋和。使用标记质子动量（极外推法）中的脉冲近似和解析性提取自由中子结构。[结果]在对撞机实验中极化标记的DIS观测值的一般表达。极化氘核低频光谱函数和核子动量分布的解析和数值研究。从标记的氘核自旋不对称中提取中子自旋结构的实用程序。[结论]观众标记为精确的中子自旋结构测量提供了新的工具。可以通过标记的质子动量依赖性消除D波去极化和核结合效应。该方法可以扩展到张量极化的可观测值，自旋轨道效应和衍射过程。