We analyze the perturbative and parametric stability of the QCD predictions for the azimuthal asymmetries in heavy quark leptoproduction. At leading order, the $\cos \phi$ asymmetry vanishes whereas the $\cos 2\phi$ one is of leading twist and predicted to be about 15% at energies sufficiently above the production threshold. We calculate the NLO soft-gluon corrections to $\phi$-dependent leptoproduction to the next-to-leading logarithmic accuracy. The soft-gluon approximation provides a good description of the available exact NLO results at $Q^{2}\lesssim m^{2}$. Our analysis shows that, contrary to the production cross sections, the $\cos 2\phi$ asymmetry is practically insensitive to soft radiation for $Q^{2}\lesssim m^{2}$ at energies of the fixed target experiments. We conclude that the $\cos 2\phi$ asymmetry is well defined in pQCD: it is stable both perturbatively and parametrically, and insensitive (in the case of bottom production) to nonperturbative contributions. Measurements of the azimuthal asymmetries would provide an excellent test of pQCD applicability to heavy flavor production.
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机译：我们分析了夸克le生产中方位角不对称的QCD预测的摄动和参数稳定性。在超前阶，$ \ cos \ phi $不对称性消失，而$ \ cos 2 \ phi $ one具有超前扭曲，并预测在足够高于生产阈值的能量下约为15％。我们计算对依赖$ \ phi $的假体生产的NLO软胶子校正，以达到对数精度的领先水平。软胶子近似可很好地描述$ Q ^ {2} \ lesssim m ^ {2} $处可用的准确NLO结果。我们的分析表明，与生产横截面相反，对于固定目标实验的能量$ Q ^ {2} \ lesssim m ^ {2} $，$ \ cos 2 \ phi $不对称实际上对软辐射不敏感。我们得出的结论是，p \ QCD中$ \ cos 2 \ phi $的不对称性得到了很好的定义：它在摄动和参数上都是稳定的，并且对非摄动贡献不敏感（在底部生产的情况下）。方位不对称性的测量将为pQCD在浓味生产中的适用性提供出色的测试。
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