TY  - EJOUR
AU  - Rehbehn, Nils-Holger
AU  - Sajith, Lakshmi Priya Kozhiparambil
AU  - Rosner, Michael K.
AU  - Cheung, Charles
AU  - Porsev, Sergey G.
AU  - Safronova, Marianna S.
AU  - Worm, Steven
AU  - Budker, Dmitry
AU  - Pfeifer, Thomas
AU  - Crespo López-Urrutia, José R.
AU  - Bekker, Hendrik
TI  - Optical transitions near the elusive 5s-4f level crossing in highly charged osmium with sensitivity to physics beyond the standard model
IS  - arXiv:2509.06710
SN  - 2469-9934
M1  - PUBDB-2026-00146
M1  - arXiv:2509.06710
PY  - 2025
N1  - 9 pages, 2 figures
AB  - Optical transitions in highly charged ions can be very sensitive to hypothetical beyond-the-standard-model phenomena. Those near the degeneracy due to the 5s-4f level crossing are especially promising. We present measurements of Os15,16,17+ ions at an electron beam ion trap and corresponding predictions of several transitions that show a high sensitivity to hypothetical fifth forces and possible violations of local Lorentz invariance. We found electric quadrupole transitions in Os16+, which are suitable for frequency metrology due to linewidths down to 44µHz. Our calculations show the need for including enough inner-shell excitations to avoid an overestimation of interconfiguration transition rates, which were too faint for detection at the present signal-to-noise ratio.
LB  - PUB:(DE-HGF)25
DO  - DOI:10.1103/p347-47ys
UR  - https://bib-pubdb1.desy.de/record/643340
ER  -