Reconciling mean-squared radius differences in the silver chain through improved measurement and ab initio calculations

• Published in: Physical review research 2024-07, Vol.6 (3), p.033040, Article 033040
• Main Authors: Ohayon, B., Padilla-Castillo, J. E., Wright, S. C., Meijer, G., Sahoo, B. K.
• Format: Article
• Language: English
• ISSN: 2643-1564; 2643-1564
• DOI: 10.1103/PhysRevResearch.6.033040

Nuclear charge radius differences in the silver isotopic chain have been reported through different combinations of experiment and theory, exhibiting a tension of two combined standard errors. This study investigates this issue by combining high-accuracy calculations for six low-lying states of atomic silver with an improved measurement of the 5 s 2 S 1 / 2 − 5 p 2 P 3 / 2 transition optical isotope shift. Our calculations predict measured electronic transition energies in Ag  at the 0.3% level, the highest accuracy achieved in this system so far. We calculate electronic isotope shift factors by employing analytical response relativistic coupled-cluster theory and find that a consistent charge radius difference between Ag 107 , 109 is returned when combining our calculations with the available optical isotope shift measurements. We therefore recommend an improved value for the mean-squared charge radius difference between Ag 107 and Ag 109 as 0.207(6) fm 2 , within one combined error from the value derived from muonic Ag experiments, and an updated set of charge radii differences across the isotopic chain.