Sensitivity to new physics of isotope-shift studies using the coronal lines of highly charged calcium ions

authored by
Nils Holger Rehbehn, Michael K. Rosner, Hendrik Bekker, Julian C. Berengut, Piet O. Schmidt, Steven A. King, Peter Micke, Ming Feng Gu, Robert Müller, Andrey Surzhykov, José R.Crespo López-Urrutia

Promising searches for new physics beyond the current standard model (SM) of particle physics are feasible through isotope-shift spectroscopy, which is sensitive to a hypothetical fifth force between the neutrons of the nucleus and the electrons of the shell. Such an interaction would be mediated by a new particle which could in principle be associated with dark matter. In so-called King plots, the mass-scaled frequency shifts of two optical transitions are plotted against each other for a series of isotopes. Subtle deviations from the expected linearity could reveal such a fifth force. Here, we study experimentally and theoretically six transitions in highly charged ions of Ca, an element with five stable isotopes of zero nuclear spin. Some of the transitions are suitable for upcoming high-precision coherent laser spectroscopy and optical clocks. Our results provide a sufficient number of clock transitions for - in combination with those of singly charged Ca+ - application of the generalized King plot method. This will allow future high-precision measurements to remove higher-order SM-related nonlinearities and open a door to yet more sensitive searches for unknown forces and particles.

Institute of Quantum Optics
CRC 1227 Designed Quantum States of Matter (DQ-mat)
External Organisation(s)
Max Planck Institute for Nuclear Physics
Johannes Gutenberg University Mainz
University of New South Wales (UNSW)
National Metrology Institute of Germany (PTB)
University of California at Berkeley
Technische Universität Braunschweig
Laboratory for Emerging Nanometrology Braunschweig (LENA)
Physical Review A
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Atomic and Molecular Physics, and Optics
Electronic version(s) (Access: Open)