https://doi.org/10.1140/epja/s10050-024-01341-3
Regular Article –Theoretical Physics
Ab initio description of monopole resonances in light- and medium-mass nuclei
II. Ab initio PGCM calculations in 
, 
and 
1
Department of Physics, Technische Universität Darmstadt, 64289, Darmstadt, Germany
2
ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany
3
IRFU, CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
4
KU Leuven, Department of Physics and Astronomy, Instituut voor Kern- en Stralingsfysica, 3001, Leuven, Belgium
5
CEA, DAM, DIF, 91297, Arpajon, France
6
Laboratoire Matière en Conditions Extrêmes, Université Paris-Saclay, CEA, 91680, Bruyères-le-Châtel, France
7
CEA, DES, IRESNE, DER, SPRC, 13108, Saint-Paul-lès-Durance, France
8
Helmholtz Forschungsakademie Hessen für FAIR, GSI Helmholtzzentrum, 64289, Darmstadt, Germany
a
aporro@theorie.ikp.physik.tu-darmstadt.de
Received:
19
March
2024
Accepted:
2
May
2024
Published online:
20
June
2024
Giant resonances (GRs) are a striking manifestation of collective motions in atomic nuclei. The present paper is the second in a series of four dedicated to the use of the projected generator coordinate method (PGCM) for the ab initio determination of the isoscalar giant monopole resonance (GMR) in closed- and open-shell mid-mass nuclei. While the first paper was dedicated to quantifying various uncertainty sources, the present paper focuses on the first applications to three doubly-open shell nuclei, namely , and . In particular, the goal is to investigate, starting from chiral effective field theory nuclear interactions, (i) the coupling of the GMR with the giant quadrupole resonance (GQR) in intrinsically-deformed nuclei, (ii) the possible impact of shape coexistence and shape mixing on the GMR, (iii) the GMR based on shape isomers and (iv) the impact of anharmonic effects on the monopole response. The latter is studied by comparing PGCM results to those obtained via the quasi-particle random phase approximation (QRPA), the traditional many-body approach to giant resonances, performed in a consistent setting. Eventually, PGCM results for sd-shell nuclei are in good agreement with experimental data, which is attributed to the capacity of the PGCM to capture the important fragmentation of the monopole response in light, intrinsically-deformed systems. Still, the comparison to data in and illustrates the challenge (and the potential benefit) of extracting unambiguous experimental information.
© The Author(s) 2024
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