Chapter IV. Coupling Effects of Two-Particle and Alpha Two-Hole States in<i>A</i>= 18 Nuclei

Sakuda, Toshimi; Nagata, Saburo; Nemoto, Fumiki

doi:10.1143/ptps.65.111

Cited by 18 publications

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“…This model treats the low-lying positive parity states of F as eigenstates of a local t+ 0 potential and reproduces well the observed properties of these states [10]. The low-lying negative parity states, e. g. , 2 (0.110 MeV), 2 (1.346 MeV), and-(1.459 MeV) states, can be considered to be n+ N cluster states [10,11] and then cannot be treated within the fralnework of the 0+4+ C three-body model. In the present analyses, therefore, these low-lying negative parity states were neglected, although significant Ps values have been obtained for the 2 state &om the DWBA analyses of the light ion inelastic data [12 -15].…”

Section: Procedures Of the Analysismentioning

confidence: 61%

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Coupled channels analysis ofF19+12
Fujita
¹
,
Katô
²
,
Sugimitsu
³

et al. 1994
Phys. Rev. C
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Angular distributions for elastic and inelastic scattering of the F+ C system leading to the (g. s. ),~( 0.197 MeV),~(1.554 MeV), and s+ (2.780 MeV) states in F were calculated with a coupled channels (CC) method using cluster folding (CF) interactions based on a ' 0+t+' C three-body model at EL, ( C)=30 -60 MeV. The calculations reproduce well the experimental angular distributions for the elastic and inelastic scattering to the~and~states at all energies, although for the inelastic scattering to the~and 2 states the phases of the calculated angular distributions seem to be shifted slightly backward from the experimental ones. The calculations are compared with the CC calculations using Woods-Saxon interaction in order to investigate the effect of the shape of the interaction.PACS number(s): 25.70.8c

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Section: Procedures Of the Analysismentioning

confidence: 61%

“…The low-lying positive parity states of F are considered to have a cluster structure of t+ 0 configuration [10,11].…”

Section: Intrgductignmentioning

confidence: 99%

Coupled channels analysis ofF19+12
Fujita
¹
,
Katô
²
,
Sugimitsu
³

et al. 1994
Phys. Rev. C
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“…(It should be noted that in cases where perturbative renormalization is employed, such as the Kuo-Brown shell model interactions [18], the results are only applied to those levels for which the model wave functions are approximately valid, and not to those where the overlap is low. For instance, the sd shell interaction is not appropriate for levels that are dominated by the non-sd shell states [19,20], even though the overlap with sd shell states is nonzero [21]). This latter situation is precisely what the supposed direct "microscopic connections" [12] of the FDSM are intended to avoid [14]; unfortunately, results to date [2,3,9] show the connections to be tenuous, and the FDSM to be firmly in that final category.…”

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confidence: 99%

“…Investigations into the goodness of symmetries, or other kinematically determined constructions, for microscopic models invariably make reference to a realistic effective interaction appropriate for the full shell model, using either the interac-tion itself or its eigenfunctions [23]. Direct analyses using eigenfunctions have been performed where practicable; examples are SU(4) [24,25], pseudo-SU(3) [26,27], seniority [28], the OAI interpretation of the IBM [29,30], and the shell model approximation itself [21,31]. Investigation using the analysis of Hamiltonians has been performed for SU(3), pseudo-SU(3), and SU(4) [23,32,33].…”

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confidence: 99%

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Reply to ‘‘Comment on ‘Comparison of realistic and symmetry-determinedSandDpairs for’156

Halse

1991

Phys. Rev. C

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I reply to the preceding Comment.The preceding Comment [1] by Chen et al. discusses two separate tests [2,3] of the so-called "fermion dynamical symmetry model" [4,5] (FDSM), one for an isospininvariant version [6 -8], in the sd shell [2] (see also Ref.[9]), the other [3] using an HFB calculation [10] for Gd. In both cases, by directly examining the assumption that ". . . coherent S and D pairs are the most important building blocks in low-energy collective states, "[11], the FDSM was found to have no microscopic justification. Chen et al. [1] seek to contest this conclusion; in this reply their comments are answered. The opinions expressed by Chen et al. [1] may be summarized as follows. 1. The basic assumption of the FDSM, that low-energy collective shell model states fa11 into a particular subspace [11,12] (a statement concerning wave functions), should not be investigated directly. The existence of effective operators capable of reproducing data should be the criterion by which the validity of this supposedly microscopic [13]model is assessed. 2. A comparison of pairs gives no indication of the overlap of many-pair states. 3. The 5+ Q Q Hamiltonian is not a sufficiently reasonable approximation to a realistic full shell model effective interaction, even for low-energy nuclear structure physics. In addition, the particular mean field solution of this [10]may not be an accurate approximation. 4. The possible FDSM symmetries in the sd shell are expected not to be realized there. Opinion 1 applies to both investigations [2,3] and is the central point, referring to any such future test. Opinions 2 and 3 apply to the ' Gd test [3] only, opinion 4 to the sd shell investigation [2]. Each point will be answered in turn. 1. The existence of effective operators is the appropriate criterion for the validity of a phenomenological model; it cannot be sufhcient for a supposedly realistic microscopic model, whose necessarily stronger statement should satisfy some additional criteria. For the FDSM, the microscopic structure employs the usual full shell model valence spaces, for which a realistic description is widely accepted as involving only a small selection of known effective interactions. (A brief discussion on the range of Hamiltonians generally considered as realistic, in this context of low-energy levels, is given in Sec. III.) The defining assumption is then that the resulting eigenfunctions can be at least approximately constructed from particular symmetry-determined S and D pairs [5] vis. ". .. coherent S and D pairs are the most important building blocks in low-energy collective states" [11], "The FDSM is, in fact, a prescription for solution of the shell model through a radical symmetry dictated truncation" [12], ". . . fully microscopic connections between these dynamical symmetries and the underlying shell structure" [13], and ". . . any dynamical symmetries relevant to nuclear structure should manifest themselves directly from the fermion degrees of freedom without explicitly introducing bosons" [14]. That the...

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Microscopic study of the α-14C molecular-dipole degree of freedom in the18O nucleus

1984

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Chapter IV. Coupling Effects of Two-Particle and Alpha Two-Hole States inA= 18 Nuclei

Cited by 18 publications

References 0 publications

Coupled channels analysis ofF19+12
Fujita
¹
,
Katô
²
,
Sugimitsu
³

et al. 1994
Phys. Rev. C
0
0
0
0
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Coupled channels analysis ofF19+12
Fujita
¹
,
Katô
²
,
Sugimitsu
³

et al. 1994
Phys. Rev. C
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0
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Reply to ‘‘Comment on ‘Comparison of realistic and symmetry-determinedSandDpairs for’156

Microscopic study of the α-14C molecular-dipole degree of freedom in the18O nucleus

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Chapter IV. Coupling Effects of Two-Particle and Alpha Two-Hole States inA= 18 Nuclei

Cited by 18 publications

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Coupled channels analysis ofF19+12Fujita1, Katô2, Sugimitsu3 et al. 1994Phys. Rev. C0000View full textAdd to dashboardCite

Coupled channels analysis ofF19+12Fujita1, Katô2, Sugimitsu3 et al. 1994Phys. Rev. C0000View full textAdd to dashboardCite

Reply to ‘‘Comment on ‘Comparison of realistic and symmetry-determinedSandDpairs for’156

Microscopic study of the α-14C molecular-dipole degree of freedom in the18O nucleus

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About

Coupled channels analysis ofF19+12
Fujita
¹
,
Katô
²
,
Sugimitsu
³

et al. 1994
Phys. Rev. C
0
0
0
0
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Coupled channels analysis ofF19+12
Fujita
¹
,
Katô
²
,
Sugimitsu
³

et al. 1994
Phys. Rev. C
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0
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