| 1. |
- Parr, E., et al.
(författare)
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Single-particle states and parity doublets in odd- Z Ac 221 and Pa 225 from α -decay spectroscopy
- 2022
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Ingår i: Physical Review C. - 2469-9985. ; 105:3
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Tidskriftsartikel (refereegranskat)abstract
- Low-lying states in the odd-Z isotopes Ac13289221 and Pa13491225 have been studied using α-particle and αγ-coincidence spectroscopy in the Pa225→Ac221→Fr217 decay chain. Ground-state spin and parity assignments of Iπ = 5/2- are proposed for both Ac221 and Pa225, with the odd proton occupying the ω = 5/2 orbital of the quadrupole-octupole deformed shell model in both nuclei. In Ac221, excited states in the bands based on the ω = 5/2 and ω = 3/2 orbitals have been identified, including proposed parity-doublet states. The results suggest that reflection-asymmetric deformation of the ground state persists in the odd-A members of the isotope chains down to N = 132 for Ac and N = 134 for Pa, before reaching the transitional region at N = 130.
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| 2. |
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| 3. |
- Butler, P. A., et al.
(författare)
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The observation of vibrating pear-shapes in radon nuclei
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.
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| 4. |
- Butler, P. A., et al.
(författare)
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Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive ^{222}Ra and ^{228}Ra Beams
- 2020
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Ingår i: Physical Review Letters. - 1079-7114. ; 124:4
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Tidskriftsartikel (refereegranskat)abstract
- There is sparse direct experimental evidence that atomic nuclei can exhibit stable "pear" shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in ^{222,228}Ra nuclei using the method of sub-barrier, multistep Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing ^{222}Ra as pear shaped with stable octupole deformation, while ^{228}Ra behaves like an octupole vibrator.
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| 5. |
- Spagnoletti, P., et al.
(författare)
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Coulomb excitation of Rn 222
- 2022
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Ingår i: Physical Review C. - 2469-9985. ; 105:2
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Tidskriftsartikel (refereegranskat)abstract
- The nature of quadrupole and octupole collectivity in Rn222 was investigated by determining the electric-quadrupole (E2) and octupole (E3) matrix elements using subbarrier, multistep Coulomb excitation. The radioactive Rn222 beam, accelerated to 4.23 MeV/u, was provided by the HIE-ISOLDE facility at CERN. Data were collected in the Miniball γ-ray spectrometer following the bombardment of two targets, Sn120 and Ni60. Transition E2 matrix elements within the ground-state and octupole bands were measured up to 10ℏ and the results were consistent with a constant intrinsic electric-quadrupole moment, 518(11)efm2. The values of the intrinsic electric-octupole moment for the 0+→3- and 2+→5- transitions were found to be respectively 2360-210+300efm3 and 2300-500+300efm3 while a smaller value, 1200-900+500efm3, was found for the 2+→1- transition. In addition, four excited non-yrast states were identified in this work via γ-γ coincidences.
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| 6. |
- Kern, R., et al.
(författare)
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Restoring the valence-shell stabilization in Nd 140
- 2020
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Ingår i: Physical Review C. - 2469-9985. ; 102:4
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Tidskriftsartikel (refereegranskat)abstract
- A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain E2 and M1 transition matrix elements of Nd140 using the multistep Coulomb-excitation code gosia. The absolute M1 strengths, B(M1;22+→21+)=0.033(8)μN2,B(M1;23+→21+)=0.26-0.10+0.11μN2, and B(M1;24+→21+)<0.04μN2, identify the 23+ state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of Nd140. The degree of F-spin mixing in Nd140 was quantified with the determination of the mixing matrix element VF-mix<7-7+13keV.
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| 7. |
- Kelly, M. M., et al.
(författare)
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Analysis of fluid-phase mediators
- 2002
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Ingår i: The European respiratory journal. Supplement. - : European Respiratory Society (ERS). - 0904-1850. ; 37, s. 24s-39s
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Tidskriftsartikel (refereegranskat)
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