Speaker
Description
I will present direct frequency-comb Raman spectroscopy of the $3d~^2D_{3/2}$ - $3d~^2D_{5/2}$ interval in all stable even isotopes of $^A$Ca$^+$ (A = 40, 42, 44, 46, and 48) [1,2]. With an accuracy of $\sim$20 Hz on the deduced isotope shifts, these data, combined with measurements of the $4s~^2S_{1/2}\leftrightarrow 3d~^2D_{5/2}$ transition ($\sim$2 kHz accuracy), allowed us to carry out a King plot analysis with unprecedented sensitivity to the coupling between electrons and neutrons by bosons beyond the Standard Model. Furthermore, we estimate that with improved spectroscopic techniques already available, King plots based on data from spectroscopy of either Ca$^+$, Ba$^+$ or Yb$^+$ should be able to probe new physics interactions mediated by bosons with masses $\geq 0.3$ MeV/c$^2$ that are so far unconstrained by other experiments.
[1] C. Solaro, S. Meyer, K. Fisher, M. V. DePalatis and M. Drewsen, ''Direct frequency-comb-driven Raman transitions in the terahertz range,'' Phys. Rev. Lett. 120, 253601 (2018).
[2] C. Solaro, S. Meyer, K. Fisher, J. C. Berengut, E. Fuchs and M. Drewsen, ''Improved isotope-shift-based bounds on bosons beyond the standard model through measurements of the $3d~^2D_{3/2}$ - $3d~^2D_{5/2}$ interval in Ca$^+$,'' Phys. Rev. Lett. 125, 123003 (2020).
