arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.11307nucl-thnucl-exphysics.data-an
收藏

设计最佳实验：在质子康普顿散射中的应用

Designing Optimal Experiments: An Application to Proton Compton Scattering

J. A. Melendez, R. J. Furnstahl, H. W. Griesshammer, J. A. McGovern, D. R. Phillips, M. T. Pratola

备注：
47 pages LaTeX2e (pdflatex) including 33 figures as .jpg files using includegraphics. Improved presentation with corrections do not affect the conclusions by details of the figures. Higher-resolution figures are available at https://home.gwu.edu/~hgrie/Compton/one-N-comprehensive-observables-delta4.v2.0.high-resolution-figures.tgz. Final version with minor corrections published in EPJA57(2021)81
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

解释测量需要物理理论，但理论的准确性可能会在实验领域有所不同。为了优化实验设计，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。我们开发了一个贝叶斯方法来解决这个问题，并将其应用到质子康普顿散射的例子。手征有效场论（$χ$ EFT）预测了这种反应的散射振幅的函数形式，因此核子的电磁极化率可以从数据中推断出来。随着光子能量的增加，实验速率和极化率的灵敏度增加，但$χ$ EFT的准确性下降。我们的基于物理的模型$χ$ EFT截断误差相结合的极化率和合理的假设在HI $γ$ S和MAMI的实验能力，以评估从测量特定的可观测量在特定的运动学，\emph{i.e.}的信息增益，以确定新的数据容易收缩的不确定性的相对量。最强的增益可能来自于自旋可观测量$Σ_{2x}$和$Σ_{2x^\prime}$的新数据，它们的能量分别为$ω\simeq140$到$200$ MeV和$40^\circ$到$120^\circ$。这些将紧密约束$γ_{E1E1}-γ_{E1M2}$。关于$100$和$200$ \、MeV和宽角度范围内的微分截面的新数据将大大改善对$α_{E1}-β_{M1}$、$γ_π$和$γ_{M1M1}-γ_{M1E2}$的约束。对于$Σ_3$和$Σ_{2z^\prime}$，在$160$ MeV附近也存在良好的信号。这些数据将是关键的，在继续寻求钉下标量极化率和完善的自旋极化率的理解。

英文摘要：

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 ($χ$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 of $χ$EFT decreases. Our physics-based model of $χ$EFT truncation errors is combined with present knowledge of the polarizabilities and reasonable assumptions about experimental capabilities at HI$γ$S and MAMI to assess the information gain from measuring specific observables at specific kinematics, \emph{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 observables $Σ_{2x}$ and $Σ_{2x^\prime}$ at $ω\simeq140$ to $200$ MeV and $40^\circ$ to $120^\circ$. These would tightly constrain $γ_{E1E1}-γ_{E1M2}$. New data on the differential cross section between $100$ and $200$\,MeV and over a wide angle range will substantially improve constraints on $α_{E1}-β_{M1}$, $γ_π$ and $γ_{M1M1}-γ_{M1E2}$. Good signals also exist around $160$ MeV for $Σ_3$ and $Σ_{2z^\prime}$. Such data will be pivotal in the continuing quest to pin down the scalar polarizabilities and refine understanding of the spin polarizabilities.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑