Near-threshold coherent photoproduction of π⁰-meson on the deuteron is investigated. Numerical results for the unpolarized differential and total cross sections, the linear photon Σ-asymmetry, the vector T₁₁ and tensor T_2M (M = 0, 1, 2) deuteron spin asymmetries, and the spin asymmetry \(\tilde{T}_{20}\) of the total cross section are presented. The role of D-wave component of the deuteron wave function on these physical observables is studied. The calculations are based on the impulse approximation in which we use the realistic and high-precision Bonn NN potential (full model) for the deuteron wave function and the unitary isobar MAID-2007 model for the elementary γN → πN amplitude that describes well the threshold region. We have found that the D-wave component has a negligible effect on the unpolarized cross sections and the vector deuteron T₁₁-asymmetry at photon lab-energies close to threshold. On the contrary, we have obtained a significant role of the D-wave part of the deuteron wave function on the Σ, T_2M, and \(\tilde{T}_{20}\) spin asymmetries. The results for the unpolarized differential cross section are compared to the experimental data from TAPS and a satisfactory agreement within the uncertainties has been obtained at forward pion angles. At backward pion angles, our results underestimate the experimental data and a disagreement has been found.

中文翻译：

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阈值附近氘核上的相干π0-光产生和氘核波函数的D波分量的作用

的近阈相干光生π ⁰ -meson在氘核进行了研究。非极化微分和总横截面，线性光子Σ不对称，矢量T ₁₁和张量T _{2 M}（M = 0，1，2）氘核自旋不对称以及自旋不对称\（\ tilde {T显示了总横截面的} _ {20} \）。研究了氘核波函数的D波分量对这些物理观测值的作用。计算基于脉冲逼近，其中我们使用逼真的高精度波恩神经网络氘波函数的势能（完整模型）和基本γN → πN振幅的单一等压线MAID-2007模型，很好地描述了阈值区域。我们发现，在接近阈值的光子实验室能量下，D波分量对非极化截面和矢量氘核T ₁₁不对称性的影响可忽略不计。相反，我们已经获得了氘核波函数的D波部分在Σ，T _{2 M}和\（\ tilde {T} _ {20} \）上的重要作用。自旋不对称。将非极化差分横截面的结果与来自TAPS的实验数据进行了比较，并且在前向子角上已获得了不确定性内的令人满意的一致性。在后倾介子角处，我们的结果低估了实验数据，并且发现了分歧。