Symmetry breaking of Gamow-Teller and magnetic-dipole transitions and its restoration in calcium isotopes

Scientific paper - Original scientific paper

• Author: Tomohiro Oishi
• Author: Ante Ravlić
• Author: Nils Paar
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

Nuclear magnetic-dipole (M1) and Gamow-Teller (GT) transitions provide insight into the spin-isospin properties of atomic nuclei. By considering them as unified spin-isospin transitions, the M1/GT transition strengths and excitation energies are subject to isospin symmetry. The excitation properties associated to the M1/GT symmetry need to be clarified within a consistent theoretical approach. In this work, the relationship between the M1 and GT transitions in Ca isotopes is investigated in a unified framework based on the relativistic energy-density functional (REDF) with point-coupling interactions, using the relativistic quasiparticle random-phase approximation (RQRPA). It is shown that the isovector-pseudovector (IV-PV) residual interaction affects both transitions, and the symmetry of M1 and giant-GT transitions is disrupted by this interaction in closed-shell nuclei. In open-shell Ca isotopes, the proton-neutron pairing in the residual RQRPA interaction also plays a role in GT transitions. Due to the interplay between these interactions, the M1/GT symmetry can be restored especially in the 42Ca nucleus, i.e., the giant-GT strength can become comparable to that of the M1 mode in terms of the unified spin-isospin transitions by adjusting the proton-neutron pairing strength to reproduce the experimental low-lying GT-excitation energies. The mirror symmetry of both M1 and GT transitions is also demonstrated for open-shell mirror partners, 42Ca and 42Ti. Further improvements are required to achieve simultaneous reproduction of M1 and GT transition energies in the REDF framework.

• Keywords (english): nuclear magnetic-dipole; Gamow-Teller (GT) transitions
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review C
• Numbering: vol. 105, no. 6, 064309
• p-ISSN: 2469-9985
• e-ISSN: 2469-9993
• DOI: https://doi.org/10.1103/PhysRevC.105.064309
• URN:NBN: urn:nbn:hr:217:541990
• Publication: 2022
• Project: Number: TTP-2018-07-3554; Title (croatian): Exotic Nuclear Structure and Dynamics; Title (english): Exotic Nuclear Structure and Dynamics; Acronym: ExoNSD; Leader: Kosuke Nomura; Jurisdiction: Croatia; Funding stream: TTP
• Project: Number: KK.01.1.1.01.0004; Title (english): QuantiXLie Center of Excellence; Acronym: QuantiXLie; Leader: Hrvoje Buljan, Pavle Pandžić; Jurisdiction: eu; Funding stream: European Regional Development Fund - the Competitiveness and Cohesion Operational Programme
• Document URL: https://link.aps.org/doi/10.1103/PhysRevC.105.064309
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2022 American Physical Society. Received 4 January 2022; Accepted 9 June 2022; Published 23 June 2022.
• Created on: 2023-08-18 17:23:28