Nonlinear Calcium King Plot Constrains New Bosons and Nuclear Properties
Abstract
Nonlinearities in King plots (KP) of isotope shifts (IS) can reveal the existence of beyond-standard-model (BSM) interactions that couple electrons and neutrons. However, it is crucial to distinguish higher-order standard model (SM) effects from BSM physics. We measure the IS of the transitions P30→P31 in Ca14+ and S21/2→D5/22 in Ca+ with sub-Hz precision as well as the nuclear mass ratios with relative uncertainties below 4×10-11 for the five stable, even isotopes of calcium (Ca40,42,44,46,48). Combined, these measurements yield a calcium KP nonlinearity with a significance of ∼103σ. Precision calculations show that the nonlinearity cannot be fully accounted for by the expected largest higher-order SM effect, the second-order mass shift, and identify the little-studied nuclear polarization as the only remaining SM contribution that may be large enough to explain it. Despite the observed nonlinearity, we improve existing KP-based constraints on a hypothetical Yukawa interaction for most of the new boson masses between 10 eV/c2 and 107 eV/c2.
Details
- Organisation(s)
-
Institute of Quantum Optics
Institute of Theoretical Physics
- External Organisation(s)
-
Physikalisch-Technische Bundesanstalt PTB
Oxford Ionics Ltd.
ETH Zurich
Max Planck Institute for Nuclear Physics
University of New South Wales (UNSW)
Technische Universität Braunschweig
- Type
- Article
- Journal
- Physical review letters
- Volume
- 134
- ISSN
- 0031-9007
- Publication date
- 10.06.2025
- Publication status
- Published
- Peer reviewed
- Yes
- ASJC Scopus subject areas
- General Physics and Astronomy
- Electronic version(s)
-
https://doi.org/10.1103/PhysRevLett.134.233002 (Access:
Open
)
