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arXiv 1911.04877nucl-thnucl-ex
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从氘核结构半径的精确计算中提取中子电荷半径

Extraction of the neutron charge radius from a precision calculation of the deuteron structure radius

A. A. Filin, V. Baru, E. Epelbaum, H. Krebs, D. Möller, P. Reinert

摘要:

本文给出了手征有效场论中氘核结构半径的高精度计算。我们的分析采用了最先进的半局域两核子势,并考虑到两体贡献的电荷密度运营商高达五阶的手征展开。五阶短程两体贡献的电荷密度算子的强度被调整到氘核电荷形状因子的实验数据。详细的误差分析进行传播的低能量常数的统计不确定性进入两个核子的潜力和估计误差的手征展开的截断,以及从核子形状因子的不确定性。利用氘结构半径的预测值和氘与质子电荷半径差的精确原子数据,我们首次从轻核中提取出中子的电荷半径。提取的值读取为$r_n^2 = - 0.106 \substack{ +0.007\\ -0.005\\} \, \text{fm}^2$,其大小约为$1.7σ$,小于粒子数据组给出的当前值。此外,由于计算的氘核电荷形状因子的高精度和仔细的系统误差分析,我们的结果开辟了一条道路,准确确定核子形状因子的弹性电子-氘核散射数据测量在美因茨微波加速器和其他实验设施。

英文摘要:

We present a high-accuracy calculation of the deuteron structure radius in chiral effective field theory. Our analysis employs the state-of-the-art semilocal two-nucleon potentials and takes into account two-body contributions to the charge density operators up to fifth order in the chiral expansion. The strength of the fifth-order short-range two-body contribution to the charge density operator is adjusted to the experimental data on the deuteron charge form factor. A detailed error analysis is performed by propagating the statistical uncertainties of the low-energy constants entering the two-nucleon potentials and by estimating errors from the truncation of the chiral expansion as well as from uncertainties in the nucleon form factors. Using the predicted value for the deuteron structure radius together with the very accurate atomic data for the difference of the deuteron and proton charge radii we, for the first time, extract the charge radius of the neutron from light nuclei. The extracted value reads $r_n^2 = - 0.106 \substack{ +0.007\\ -0.005\\} \, \text{fm}^2$ and its magnitude is about $1.7σ$ smaller than the current value given by the Particle Data Group. In addition, given the high accuracy of the calculated deuteron charge form factor and its careful and systematic error analysis, our results open the way for an accurate determination of the nucleon form factors from elastic electron-deuteron scattering data measured at the Mainz Microtron and other experimental facilities.

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。

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