Designing optimal experiments: an application to proton Compton scattering
Designing optimal experiments: an application to proton Compton scattering
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DOI：
10.1140/epja/s10050-021-00382-2
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
J. Melendez;R. Furnstahl;H. Grießhammer;J. McGovern;D. Phillips;M. Pratola
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文献类型：
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作者：
J. Melendez;R. Furnstahl;H. Grießhammer;J. McGovern;D. Phillips;M. Pratola
解释测量结果需要物理理论，但该理论的准确性可能因实验领域而异。为了优化实验设计，并确保现代实验所需的大量资源集中在获取最有价值的数据上，必须考虑理论不确定性和实验误差的预期模式。我们开发了解决此问题的贝叶斯方法，并将其应用于质子康普顿散射的示例。手性有效场理论 (EFT) 预测了该反应的散射振幅的函数形式，以便可以从数据推断核子的电磁极化率。随着光子能量的增加，实验速率和对极化率的敏感性都会增加，但 EFT 的准确性会降低。我们基于物理的 EFT 截断误差模型与极化率的现有知识以及 HIS 和 MAMI 实验能力的合理假设相结合，以评估在特定运动学下测量特定可观测值所获得的信息增益，即确定新数据倾向于缩小不确定性的相对量。最强劲的收益可能来自自旋可观测值 200 MeV 和 to 的新数据。这些都会受到严格的约束。 100 至 200 MeV 之间以及较宽角度范围内的差分截面的新数据将大大改善对 和 的约束。良好的信号也存在于 160 MeV 左右。这些数据对于持续探索标量极化率和完善对自旋极化率的理解至关重要。
Interpreting measurements requires a physical theory, but the theory’s accuracy may vary across the experimental domain. To optimize experimental design, and so to ensure that the substantial resources necessary for modern experiments are focused on acquiring the most valuable data, both the theory uncertainty and the expected pattern of experimental errors must be considered. We develop a Bayesian approach to this problem, and apply it to the example of proton Compton scattering. Chiral Effective Field Theory (EFT) predicts the functional form of the scattering amplitude for this reaction, so that the electromagnetic polarizabilities of the nucleon can be inferred from data. With increasing photon energy, both experimental rates and sensitivities to polarizabilities increase, but the accuracy ofEFT decreases. Our physics-based model ofEFT truncation errors is combined with present knowledge of the polarizabilities and reasonable assumptions about experimental capabilities at HIS and MAMI to assess the information gain from measuring specific observables at specific kinematics,i.e.to determine the relative amount by which new data are apt to shrink uncertainties. The strongest gains would likely come from new data on the spin observablesandatto 200 MeV andto. These would tightly constrain. New data on the differential cross section between 100 and 200 MeV and over a wide angle range will substantially improve constraints on,and. Good signals also exist around 160 MeV forand. Such data will be pivotal in the continuing quest to pin down the scalar polarizabilities and refine understanding of the spin polarizabilities.