Electric-Monopole Transitions in Atomic Nuclei

Church, E. L.; Weneser, J.

doi:10.1103/physrev.103.1035

Cited by 233 publications

(44 citation statements)

References 27 publications

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“…The IC process for E0 occurs primarily through the 1s(K) and 2s(L 1 ) shells. Typical probabilities [14][15][16] for IC in the various atomic subshells are P K :P L1 :P L2 :P L3 : P M1 = 0.83 : 0.13 : 10 −3 : 10 −9 : 0.04. The E0 transition rate,…”

Section: A Introductionmentioning

confidence: 99%

Electric monopole transitions from low energy excitations in nuclei

Wood

Zganjar

Coster³

et al. 1999

Nuclear Physics A

231

223

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Electric monopole (E0) properties are studied across the entire nuclear mass surface. Besides an introductory discussion of various model results (shell model, geometric vibrational and rotational models, algebraic models), we point out that many of the largest E0 transition strengths, ρ 2 (E0), are associated with shape mixing. We discuss in detail the manifestation of E0 transitions and present extensive data for : single-closed shell nuclei, vibrational nuclei, well-deformed nuclei, nuclei that exhibit sudden ground-state changes, and nuclei that exhibit shape coexistence and intruder states. We also give attention to light nuclei, odd-A nuclei, and illustrate a suggested relation between ρ 2 (E0) and isotopic shifts.

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Section: A Introductionmentioning

confidence: 99%

Electric monopole transitions from low energy excitations in nuclei

Wood

Zganjar

Coster³

et al. 1999

Nuclear Physics A

231

223

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“…The coefficient σ depends on the assumed nuclear charge distribution but in any reasonable case it is smaller than 0.1 and can be neglected if the leading term is not too small [1]. The charge radius of a state |s is given by…”

mentioning

confidence: 99%

“…For transition energies greater than 2m e c 2 , electronpositron pair creation is also possible; two-photon emission is possible at all energies but extremely improbable. The total probability for a transition between initial and final states |i and |f can be separated into an electronic and a nuclear factor, P = Ωρ 2 , where the nuclear factor ρ is [1] …”

mentioning

confidence: 99%

Correlating Radii and Electric Monopole Transitions of Atomic Nuclei

et al. 2008

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A systematic analysis of the spherical-to-deformed shape phase transition in even-even rare-earth nuclei from 58Ce to 74W is carried out in the framework of the interacting boson model. These results are then used to calculate nuclear radii and electric monopole (E0) transitions with the same effective operator. The influence of the hexadecapole degree of freedom (g boson) on the correlation between radii and E0 transitions thus established, is discussed.PACS numbers: 21.10. Ft, 21.10.Ky, 21.60.Ev, 21.60.Fw Electric monopole (E0) transitions between nuclear levels proceed mainly by internal conversion with no transfer of angular momentum to the ejected electron. For transition energies greater than 2m e c 2 , electronpositron pair creation is also possible; two-photon emission is possible at all energies but extremely improbable. The total probability for a transition between initial and final states |i and |f can be separated into an electronic and a nuclear factor, P = Ωρ 2 , where the nuclear factorwith R = r 0 A 1/3 (r 0 = 1.2 fm) and where the summation runs over the Z protons in the nucleus. The coefficient σ depends on the assumed nuclear charge distribution but in any reasonable case it is smaller than 0.1 and can be neglected if the leading term is not too small [1]. The charge radius of a state |s is given byIt is found experimentally that the addition of neutrons produces a change in the nuclear charge distribution, an effect which can be parametrized by means of neutron and proton effective charges e n and e p in the charge radius operatorT (r 2 ). This leads to the following generalization of Eq. (2):where the sum is over all nucleons and e k = e n (e p ) if k is a neutron (proton). An obvious connection between ρ and the nuclear charge radius is established in the approximation σ = 0 (which henceforth will be made). Again because of the polarization effect of the neutrons, one introduces an E0 operator of the form [2]The ρ defined in Eq.(1) with σ = 0 is then given by ρ = f|T (E0)|i /eR 2 . The basic hypothesis of this Letter is to assume that the effective nucleon charges in the charge radius and E0 transition operators are the same. If this is so, comparison of Eqs. (3) and (4) leads to the relationAt present, a quantitative test of the correlations between radii and E0 transitions implied by (5) cannot be obtained in the context of the nuclear shell model. The main reason is that E0 transitions between states in a single harmonic-oscillator shell vanish identically [3] and a non-zero E0 matrix element is obtained only if valence nucleons are allowed to occupy at least two oscillator shells. This renders the shell-model calculation computationally challenging (if not impossible), certainly in the heavier nuclei which are considered here. We have therefore chosen to test the implied correlations in the context of a simpler approach, namely the interacting boson model (IBM) of atomic nuclei [4]. In this model low-lying collective excitations of nuclei are described in terms of N b bosons distrib...

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“…2) and from the γ-times (relative to the beta-triggers) of 511 keV photons, many of them following the annihilation of positrons originating from E0 transition. Based on tabulated [13][14][15] electronic factors Γ IC =3.68x107 s −1 and Γ IPF =2.69x109 s −1 , the monopole strength ρ 2 (E0,0 + 2 →0 + 1 )=13.0(0.9) 10 −3 is extracted. A 607 keV gamma peak corresponding to the transition from the 2 + 1 state at 3326 keV to the 0 + 2 state is observed with a very small intensity in the gamma spectrum with a multiplicity higher than 2 for the Si detectors.…”

Section: Experimental Setup and Resultsmentioning

confidence: 99%

Properties of Intruder States in ³⁴Al and ³⁴Si

Rotaru¹,

Lică²,

Negoiţă³

et al. 2015

Proceedings of the Conference on Advances in Radioactive Isotope Science (ARIS2014)

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We report on two experimental results for nuclei located in the region of the N=20 island of inversion. In the first experiment, performed at GANIL, we have discovered and studied the 0 + 2 state in 34 Si and made the hypothesis that it was fed by the beta-decay of a predicted isomeric 1 + state in 34 Al. In the second experiment, performed at ISOLDE, we have studied the beta-decay of 34 Mg in order to obtain information on the structure of 34 Al and in particular the position of the isomeric 1 + state.

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Electric-Monopole Transitions in Atomic Nuclei

Cited by 233 publications

References 27 publications

Electric monopole transitions from low energy excitations in nuclei

Electric monopole transitions from low energy excitations in nuclei

Correlating Radii and Electric Monopole Transitions of Atomic Nuclei

Properties of Intruder States in ³⁴Al and ³⁴Si

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Electric-Monopole Transitions in Atomic Nuclei

Cited by 233 publications

References 27 publications

Electric monopole transitions from low energy excitations in nuclei

Electric monopole transitions from low energy excitations in nuclei

Correlating Radii and Electric Monopole Transitions of Atomic Nuclei

Properties of Intruder States in 34Al and 34Si

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Properties of Intruder States in ³⁴Al and ³⁴Si