We present first measurements of the double ratio of the polarization transfer components $(P^{\prime}_{\!x} \!/ P^{\prime}_{\!z} )_p/ (P^{\prime}_{\!x} \!/ P^{\prime}_{\!z} )_s$ for knock-out protons from $s$ and $p$ shells in $^{12}{\rm C}$ measured by the $^{12}{\rm C}(\vec{e},{e}'\vec{p}\,)$ reaction in quasi-elastic kinematics. The data are compared to theoretical predictions in relativistic distorted-wave impulse approximation. Our results show that differences between $s$- and $p$-shell protons, observed when compared at the same initial momentum (missing momentum) largely disappear when the comparison is done at the same proton virtuality. We observe no density-dependent medium modifications for protons from $s$ and $p$ shells with the same virtuality in spite of the large differences in the respective nuclear densities.

中文翻译：

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从 s 和 p 壳中提取质子的 C12(e→,e′p→) 过程中反冲极化的比较

我们首次测量了极化传输分量的双倍比率 $(P^{\prime}_{\!x} \!/ P^{\prime}_{\!z} )_p/ (P^{\ prime}_{\!x} \!/ P^{\prime}_{\!z} )_s$ 用于从 $^{12}{\rm C 中的 $s$ 和 $p$ 壳中敲除质子}$ 由准弹性运动学中的 $^{12}{\rm C}(\vec{e},{e}'\vec{p}\,)$ 反应测量。将数据与相对论畸变波脉冲近似中的理论预测进行比较。我们的结果表明，在相同的初始动量（缺失动量）下进行比较时观察到的 $s$- 和 $p$-壳质子之间的差异在相同质子虚拟性下进行比较时基本上消失了。尽管各自的核密度存在很大差异，但我们没有观察到来自具有相同虚拟性的 $s$ 和 $p$ 壳的质子的密度依赖性介质修改。