https://doi.org/10.1140/epja/s10050-023-01000-z
Regular Article – Experimental Physics
A new avenue in the search for CP violation: Mössbauer spectroscopy of 
Ac
1
School of Computing, Engineering, and Physical Sciences, University of the West of Scotland, High Street, PA11 3PX, Paisley, UK
2
SUPA, Scottish Universities Physics Alliance, Aberdeen, UK
3
Department of Physics, University of York, YO10 5DD, Heslington, UK
4
Department of Physics, University of Warsaw, 02-093, Warsaw, Poland
5
Materials Theory, ETH Zürich, 8093, Zürich, Switzerland
6
National Physical Laboratory, TW11 0LW, Teddington, UK
7
Biological and Environmental Sciences, University of Stirling, FK9 4LA, Stirling, UK
Received:
18
November
2022
Accepted:
5
April
2023
Published online:
26
May
2023
This work proposes a new avenue in the search for CP-violating odd-electric and even-magnetic nuclear moments. A promising candidate to find such moments in the ground state is the quadrupole-deformed and octupole-correlated nucleus 227-actinium. In this nucleus, the 27.4-keV E1 transition that connects the 
parity-doublet partner and the 
ground state is perfectly suited to apply the sensitive technique of recoil-free selfabsorption, commonly known as Mössbauer spectroscopy. In this experimental approach, the lifetime of the upper parity-doublet partner allows an estimate of the lower limit of 
= 
eV for the achievable energy resolution to be made. This resolution must be exceeded by the interaction of a CP-violating moment and the corresponding multipole moment of the field distribution in the lattice. This work presents the first ideas for patterns caused by CP-violating moments on the expected quadrupole splitting and nuclear Zeeman effect.
Topical Issue: Nuclear Photonics: Overview and Perspectives Maria Jose Garcia Borge, Kazuo A. Tanaka, Calin Ur and Andreas Zilges (Guest editors).
© The Author(s) 2023
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