https://doi.org/10.1140/epja/s10050-025-01646-x
Regular Article - Theoretical Physics
Mirror-skin thickness: a possible observable sensitive to the charge symmetry breaking energy density functional
1
RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), 351-0198, Wako, Japan
2
Department of Physics, Graduate School of Science, The University of Tokyo, 113-0033, Tokyo, Japan
3
Department of Physics, Kyoto University, 606-8502, Kyoto, Japan
4
RIKEN Nishina Center, 351-0198, Wako, Japan
5
Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133, Milano, Italy
6
INFN, Sezione di Milano, Via Celoria 16, 20133, Milano, Italy
7
Center for Mathematics and Physics, University of Aizu, 965-8560, Aizu-Wakamatsu, Japan
Received:
11
March
2025
Accepted:
9
July
2025
Published online:
28
July
2025
We propose a new observable, named the mirror-skin thickness, in order to extract the strength of the charge symmetry breaking (CSB) term in an energy density functional (EDF). The mirror-skin thickness of 
isotones and 
isotopes is studied by using Hartree-Fock-Bogoliubov (HFB) calculations with various Skyrme EDFs and adding CSB and charge independence breaking (CIB) terms. It is shown that the mirror-skin thickness is sensitive only to the CSB EDF, but hardly depends on either the isospin symmetric part of the nuclear EDF or the CIB term. Therefore, this observable can be used to extract the magnitude of the CSB term in the EDF quantitatively, either from experimental data or ab initio calculations. We have studied the accuracy in the mirror-skin thickness that is needed to extract sensible information. Our study may also help to understand the inconsistency between the strength of the phenomenological CSB and that extracted from ab initio calculations [Naito et al. Nuovo. Cim. C 47, 52 (2024)]. Among possible mirror pairs for experimental study, we propose the mirror-skin thickness between 
and 
, which could be accessed in future experiments in RIBF and/or FRIB.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
