纵向极化HD上极化光子π介子产生的测量及其对GDH积分收敛性的影响

Measurement of the high-energy contribution to the Gerasimov-Drell-Hearn sum rule

We propose to measure the high-energy behavior of the integrand of the Gerasimov-Drell-Hearn (GDH) sum rule on the proton and the neutron up to 12 GeV. The convergence of the GDH integral will be investigated for the first time and to high precision. The validity of the GDH sum rule on the neutron will be accurately tested for the first time, while for the proton the uncertainty will be improved by $25\%$ relative. The data will allow precision testing of Regge phenomenology in the polarized domain. The $a_1$ and $f_1$ Regge trajectory intercepts will be obtained to an order of magnitude highe…

氘核、质子和中子广义Gerasimov-Drell-Hearn积分的$Q^2$依赖性

The $Q^2$-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron

Gerasimov-Drell-Hearn（GDH）求和规则将对靶核磁矩的异常贡献与螺旋度相关的光吸收截面的差异的能量加权积分联系起来。HERMES收集的数据与氘靶一起提出了重新分析以前的测量质子。这提供了一个广义GDH积分覆盖同时核子共振和深非弹性散射区域的测量。随着$Q^2$的增加，核子共振区的贡献迅速减小。DIS的贡献在整个测量范围内是相当大的，甚至下降到最低的测量$Q^2$。正如预期的那样，在更高的$Q^2$的数据被发现是与以前的测量值的一阶矩的$g_1$。根据氘核和质子的数据，推导出了中子的GDH积分，并评估了质子-中子的差异。发现这种差异满足基本的比约肯求和规则在$Q^2 = 5$ GeV $^2$。

质子的纵向极化光子含量

Accessing the Longitudinally Polarized Photon Content of the Proton

本文研究了轻子-质子纵向极化散射的QED-Compton过程（QEDCS），证明了QEDCS的截面可以用质子的极化等效光子分布来表示.我们提供了必要的运动学约束，以提取质子的极化光子含量使用这个过程在HERMES，COMPASS和ERHIC。我们还讨论了虚康普顿散射的主要背景过程的抑制。指出在未来的eRHIC极化对撞机上，这样的实验可以提供小$x_B$、宽$Q^2$区的$g_1(x_B, Q^2)$的有价值的信息，特别是在固定靶实验中的低$Q^2$、中$x_B$区的信息.

Single-pion contribution to the Gerasimov--Drell--Hearn sum rule and related integrals

Phenomenological amplitudes obtained in partial-wave analyses (PWA) of single-pion photoproduction are used to evaluate the contribution of this process to the Gerasimov-Drell-Hearn (GDH), Baldin and Gell-Mann-Goldberger-Thirring (GGT) sum rules, by integrating up to 2 GeV in photon energy. Our study confirms that the single-pion contribution to all these sum rules converges even before the highest considered photon energy, but the levels of saturation are very different in the three cases. Single-pion production almost saturates the GDH sum rule for the proton, while a large fraction is missi…

纵向极化氘靶上π介子和K介子半包容电产生中单自旋方位角不对称性的测量

Measurement of single-spin azimuthal asymmetries in semi-inclusive electroproduction of pions and kaons on a longitudinally polarised deuterium target

在纵向极化氘靶的深度非弹性散射中，测量了$π^+$，$π^-$，$π^0$和$K^+$介子的半包容电生的单自旋不对称性.强子在虚光子方向上相对于轻子散射面的方位角$ϕ$上的分布出现了不对称性。横截面的$\sin ϕ$矩的相应分析功效为：$π^+$的$0.012 \pm 0.002 {(stat.)} \pm 0.002 {(syst.)}$、$π^-$的$0.006 \pm 0.003 {(stat.)} \pm 0.002 {(syst.)}$、$π^0$的$0.021 \pm 0.005 {(stat.)} \pm 0.003 {(syst.)}$和$K^+$的$0.013 \pm 0.006 {(stat.)} \pm 0.003 {(syst.)}$。对于所有粒子，$\sin 2ϕ$矩与零相容。

双光子交换与纵向极化电子在极化氘核上的弹性散射

Two-photon exchange and elastic scattering of longitudinally polarized electron on polarized deuteron

本文在单光子+双光子交换近似下研究纵向极化电子与极化氘核的弹性散射，发现双光子交换对结构函数A和B的贡献分别为百分之几和10%--20%，并揭示T_{22}及T_{11}、C_{21}、C_{22}等极化观测量的主要来源。