Field-shift factors and nuclear charge-radius difference in 3He and 4He
摘要
Precise nuclear charge radii provide stringent constraints on nuclear structure and few-body nuclear calculations.Their extraction from isotope-shift measurements relies critically on an accurate evaluation of the atomic field-shift factors.In this work,we present high-precision calculations of the field-shift factors for the helium isotopes 3He and 4He,including second-order relativistic perturbative corrections.For the 23S-23P transition,we achieve ppm-level accuracy and obtain field-shift factors of-1212.291(1)kHz/fm2 for 3He and-1212.455(1)kHz/fm2 for 4He.Using these improved values,we re-evaluate the difference of the squared nuclear charge radii to ΔR2=1.0736(21)fm2 based on the latest electronic-helium isotope-shift measurement.The resulting value is currently limited mainly by experimental uncertainty and shows a 2.76 tension with the determination from muonic-helium spectroscopy.Our results provide an improved nuclear-size benchmark for helium isotopes and highlight the importance of further high-precision nuclear and atomic studies to achieve a consistent determination of nuclear charge radii across different probes.
年，卷(期)：
2026, 37(10)
机标分类号：
O241
R445.1
R735.37
在线出版日期：
2026年10月16日
