Isoscalar monopole and dipole transitions in Mg-24, Mg-26, and Si-28

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10439385" target="_blank" >RIV/00216208:11320/21:10439385 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=VaoHeCPVWz" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=VaoHeCPVWz</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevC.103.044315" target="_blank" >10.1103/PhysRevC.103.044315</a>

Result language

angličtina

Original language name

Isoscalar monopole and dipole transitions in Mg-24, Mg-26, and Si-28

Original language description

Background: Nuclei in the sd shell demonstrate a remarkable interplay of cluster and mean-field phenomena. The N = Z nuclei, such as Mg-24 and Si-28, have been the focus of the theoretical study of both phenomena in the past. A variety of different cluster structures in these nuclei are predicted, characterized by isoscalar dipole and monopole transitions. For example, low-energy isoscalar vortical dipole states were predicted in Mg-24. The cluster and vortical mean-field phenomena can be probed by excitation of isoscalar monopole and dipole states in scattering of isoscalar particles such as deuterons or alpha particles. Purpose: We investigate, both experimentally and theoretically, the isoscalar dipole IS1 and monopole IS0 strengths in three essentially different light nuclei with different properties: stiff prolate Mg-24, soft prolate Mg-26, and soft oblate Si-28. We analyze possible manifestations of clustering and vorticity in these nuclei. Methods: Inelastically scattered alpha particles were momentum analyzed in the K600 magnetic spectrometer at iThemba LABS, Cape Town, South Africa. The scattered particles were detected in two multiwire drift chambers and two plastic scintillators placed at the focal plane of the K600. In the theoretical discussion, the Skyrme quasiparticle random-phase approximation (QRPA) and antisymmetrized molecular dynamics + generator coordinate method (AMD + GCM) were used. Results: A number of isoscalar monopole and dipole transitions were observed in the nuclei studied. Using this information, suggested structural assignments have been made for the various excited states. IS1 and IS0 strengths obtained within QRPA and AMD + GCM are compared with the experimental data. The QRPA calculations lead us to conclude that (i) the mean-field vorticity appears mainly in dipole states with K = 1, (ii) the dipole (monopole) states should have strong deformation-induced octupole (quadrupole) admixtures, and (iii) near the alpha -particle threshold there should exist a collective state with K = 0 for prolate nuclei and K = 1 for oblate nuclei, with an impressive octupole strength. The results of the AMD + GCM calculations suggest that some observed states may have a mixed (mean-field + cluster) character or correspond to particular cluster configurations. Conclusion: A tentative correspondence between observed states and theoretical states from QRPA and AMD + GCM was established. The QRPA and AMD + GCM analysis shows that low-energy isoscalar dipole states combine cluster and mean-field properties. The QRPA calculations show that the low-energy vorticity is well localized in Mg-24, fragmented in Mg-26, and absent in Si-28.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10300 - Physical sciences

Project

<a href="/en/project/GA19-14048S" target="_blank" >GA19-14048S: Theoretical and experimental search for new features of electromagnetic nuclear excitations</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physical Review C

ISSN

2469-9985

e-ISSN

—

Volume of the periodical

103

Issue of the periodical within the volume

4

Country of publishing house

US - UNITED STATES

Number of pages

18

Pages from-to

044315

UT code for WoS article

000647602200001

EID of the result in the Scopus database

2-s2.0-85104801667