We investigate coherent π0-photoproduction on the deuteron near threshold with special emphasis on beam-target double spin asymmetries. We present results for the spin asymmetries $T^{c}_{1M}$ (M = 0, 1) for circular polarized photons and vector polarized deuterons, $T^{c}_{2M}$ (M = 1, 2) for circular polarized photons and tensor polarized deuterons, $T^{l}_{1M}$ (M = 0, ± 1) for longitudinal polarized photons and vector polarized deuterons, and $T^{l}_{2M}$ (M = 0, ± 1, ± 2) for longitudinal polarized photons and tensor polarized deuterons in the γd → π0d reaction near threshold. We also discuss the sensitivity of the estimated results to the D-wave component of the deuteron wave function. The unitary isobar MAID-2007 model is used for the elementary γN → πN amplitude. This model is parameterized in terms of invariant amplitudes and allows one to give a more reliable description of the threshold region. The realistic and high-precision Bonn NN potential (full model) is used for the deuteron wave function. We have found that the D-wave component of the deuteron wave function has a little effect on the $T^{c}_{1M}$ (M = 0, 1) and $T^{l}_{2M}$ (M = 0, 1, 2) spin asymmetries. On the contrary, we have obtained a significant role of the D-wave component on the spin asymmetries $T^{c}_{2M}$ (M = 1, 2), $T^{l}_{1M}$ (M = 0, ± 1), and $T^{l}_{2M}$ (M = − 1,− 2).

中文翻译：

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反应中的射束-目标双自旋不对称性 γd → π0d 接近阈值以及氘核波函数的 D 波分量的作用

我们研究了氘核附近阈值上的相干 π0 光产生，特别强调了光束-目标双自旋不对称性。我们给出了圆极化光子和矢量极化氘核的自旋不对称性 $T^{c}_{1M}$ (M = 0, 1) 的结果 $T^{c}_{2M}$ (M = 1, 2) 对于圆极化光子和张量极化氘核，对于纵向极化光子和矢量极化氘核，$T^{l}_{1M}$ (M = 0, ± 1)，以及 $T^{l}_{2M} $ (M = 0, ± 1, ± 2) 对于阈值附近的 γd → π0d 反应中的纵向偏振光子和张量偏振氘核。我们还讨论了估计结果对氘核波函数的 D 波分量的敏感性。幺正等压线 MAID-2007 模型用于基本 γN → πN 振幅。该模型根据不变幅度进行参数化，并允许对阈值区域进行更可靠的描述。氘核波函数采用逼真且高精度的波恩神经网络势（全模型）。我们发现氘核波函数的D波分量对$T^{c}_{1M}$(M = 0, 1)和$T^{l}_{2M}$影响不大(M = 0, 1, 2) 自旋不对称。相反，我们已经获得了 D 波分量对自旋不对称性的重要作用 $T^{c}_{2M}$ (M = 1, 2), $T^{l}_{1M}$ (M = 0, ± 1) 和 $T^{l}_{2M}$ (M = − 1, − 2)。我们发现氘核波函数的D波分量对$T^{c}_{1M}$(M = 0, 1)和$T^{l}_{2M}$影响不大(M = 0, 1, 2) 自旋不对称。相反，我们已经获得了 D 波分量对自旋不对称性的重要作用 $T^{c}_{2M}$ (M = 1, 2), $T^{l}_{1M}$ (M = 0, ± 1) 和 $T^{l}_{2M}$ (M = − 1, − 2)。我们发现氘核波函数的D波分量对$T^{c}_{1M}$(M = 0, 1)和$T^{l}_{2M}$影响不大(M = 0, 1, 2) 自旋不对称。相反，我们已经获得了 D 波分量对自旋不对称性的重要作用 $T^{c}_{2M}$ (M = 1, 2), $T^{l}_{1M}$ (M = 0, ± 1) 和 $T^{l}_{2M}$ (M = − 1, − 2)。