Isospin symmetry breaking energy density functional based on quantum chromodynamics

5 Mar 2025, 15:05
1m
Main Lecture Hall (University of Aizu)

Main Lecture Hall

University of Aizu

90 Kamiiawase, Tsuruga, Itsukimachi, Aizu-Wakamatsu, Fukushima, 965-0006 Japan.

Speaker

Dr Tomoya Naito (RIKEN iTHEMS)

Description

The isospin symmetry of atomic nuclei is broken due to the Coulomb interaction and the isospin symmetry breaking part of the nuclear interaction. The former gives the dominant contribution to the isospin symmetry breaking of atomic nuclei, and the latter is a small part of the whole; however, it sometimes gives important contributions to nuclear properties, such as the mass difference of mirror nuclei and the isobaric analog states [1, 2]. Especially, it has been a long-standing problem that the Coulomb interaction is not enough to describe the mass difference of mirror nuclei, which is known as the Okamoto-Nolen-Schiffer anomaly [3, 4]. It also contributes to the slope parameter of the symmetry energy, which is known as the L parameter, affecting the neutron-skin thickness non-negligibly [2]. The isospin symmetry breaking can be classified into two parts: the charge symmetry breaking and the charge independence breaking.
Recently, we pinned down the effective interaction, i.e., the energy density functional, of charge symmetry breaking interaction using the effective mass in medium of nucleons calculated based on the quantum chromodynamics sum rule [5]. We also estimated the energy density functional of the charge independence breaking based on the quantum electrody- namics effects in the one-pion exchange potential [6], where we can, in principle, consider the effective mass of pions in medium.
In this talk, I will report our recent progress on the derivation of the isospin symmetry breaking energy density functional based on quantum chromodynamics.

Reference
[1] X. Roca-Maza, G. Colò, and H. Sagawa. “Nuclear Symmetry Energy and the Breaking of the Isospin Symmetry: How Do They Reconcile with Each Other?” Phys. Rev. Lett. 120, 202501 (2018).
[2] T. Naito, G. Colò, H. Liang, X. Roca-Maza, and H. Sagawa. “Effects of Coulomb and isospin symmetry breaking interactions on neutron-skin thickness”, Phys. Rev. C 107, 064302 (2023).
[3] K. Okamoto. “Coulomb energy of He3 and possible charge asymmetry of nuclear forces”, Phys. Lett. 11, 150 (1964).
[4] J. A. Nolen, Jr. and J. P. Schiffer. “Coulomb energies”, Annu. Rev. Nucl. Sci. 19, 471 (1969).
[5] H. Sagawa, T. Naito, X. Roca-Maza, and T. Hatsuda. “QCD-based charge symmetry breaking interaction and the Okamoto-Nolen-Schiffer anomaly”, Phys. Rev. C 109, L011302 (2024).
[6] T. Naito, G. Colò, T. Hatsuda, X. Roca-Maza, and H. Sagawa. To be submitted.

Type of contribution
Are you a student or postdoc? yes

Primary author

Dr Tomoya Naito (RIKEN iTHEMS)

Co-authors

Prof. Gianluca Colò (Università degli Studi di Milano and INFN) Prof. Tetsuo Hatsuda (RIKEN iTHEMS) Prof. Xavier Roca-Maza (Università degli Studi di Milano, INFN, and Universitat de Barcelona) Prof. Hiroyuki Sagawa (RIKEN and University of Aizu)

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