https://doi.org/10.1140/epjp/s13360-024-04887-9
Regular Article
Probing isoscalar giant monopole resonance in axially and triaxially deformed zirconium isotopes
1
High Energy Physics and Astrophysics Laboratory, Department of Physics, Faculty of Sciences Semlalia, Cadi Ayyad University, 40000, Marrakesh, Morocco
2
ERMAM, Polydisciplinary Faculty of Ouarzazate, Ibn Zhor University, P.O.B 638, Ouarzazate, Morocco
Received:
8
November
2023
Accepted:
8
January
2024
Published online:
22
January
2024
Numerical calculations of the isoscalar giant monopole resonance (ISGMR) strength in even-even Zr isotopes are presented using the quasiparticle finite amplitude method based on the deformed relativistic Hartree–Bogoliubov theory, employing the DD-PCX and DD-PC1 effective interactions. A satisfactory agreement with the available experimental ISGMR strength is achieved for 
Zr. Through constraint calculations in the (
,
)-plan, we identify local minima corresponding to axial and triaxial shapes in the even-even Zr isotopes. A soft monopole mode observed near 15 MeV in 
Zr and around 13 MeV in 
Zr can be explained not only by the deformation-induced coupling between the ISGMR and the isoscalar giant quadrupole resonance (ISGQR) strength, but also by the influence of neutron excess. The ISGMR is best described by the DD-PCX force, having a low value of the incompressibility value of 
= 213 MeV and of the Dirac mass ratio 
= 0.559. Furthermore, a transition in the positions of the soft and main ISGMR due to the kind of nuclear deformation is also observed. Additionally, the transition density of the soft monopole mode indicates that the nucleons vibrate in a distinct phase near the surface region. This phenomenon, generated by quadrupole vibrations, can be also considered as a manifestation of another monopole vibration.
Y. El Bassem, A. El Batoul and M. Oulne have contributed equally to this work.
Copyright comment 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.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. 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.
