2025/09/10 by Stefania Gravina, Gravina, Stefania, A. Castrillo +3
Physics and Astronomy · #Advanced Frequency and Time Standards #Atomic Physics (physics.atom-ph) #Atomic and Molecular Physics #Atomic and Subatomic Physics Research #FOS: Physical sciences
paper · pdf · doi:10.48550/arxiv.2509.08622
openalex publication_date 2025/09/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Precision isotope shift metrology in the deep-UV region has been performed for all bosonic isotopes of mercury with a zero nuclear spin, by using the technique of frequency-comb referenced, wavelength-modulated, saturated absorption spectroscopy. The absolute center frequencies of the 6s2 1S0 → 6s6p 3P1 intercombination line have been measured with precision in the range of 2.5 - 5.9 10-12, in temperature-stabilized mercury vapor samples with natural abundances. Frequency shifts in four isotope pairs have been determined with unprecedented accuracy, the global uncertainty being improved by a factor greater than 20 with respect to the best experimental data of the past literature. Our data set, when combined with previous measurements on the 6s6p 3P2→6s7s 3S1 transition at 546 nm, allows us to build a King plot that reveals a nonlinearity with a statistical significance of 4.6σ.