Electroexcitation of the 0+ (3.562 MeV) level of 6Li and its application to the reaction 6Li(γ, π+)6He

Bergstrom, J.C.; Auer, I.P.; Hicks, R. S.

doi:10.1016/0375-9474(75)90537-0

Cited by 73 publications

(17 citation statements)

References 20 publications

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“…The shape of the inelastic form factor is nicely reproduced but the calculation underestimates the experimental value [27]. Our inelastic form factor is very similar to where B=5968.7 s and A= -1.2573.…”

Section: Results Of Calculationsupporting

confidence: 65%

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Neutron-proton halo structure of the 3.563-MeV0+state inLi6
Arai
¹
,
Suzuki
²
,
Varga
³

1995
Phys. Rev. C
78
5
30
1
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We explore the possibility that a stable nucleus has halolike structure in high isospin excited states. As an example the structure of the 3.563-MeV 0+ state of I i is studied in a fully microscopic n+p+n three-cluster model, because it is an isobaric analog state of He with two-neutron halo structure. An extensive calculation with isospin mixing has shown that the state has spatially extended halolike structure formed by the neutron and the proton outside the o. particle. Electron scattering form factors related with the state are reproduced fairly well.PACS number(s): 21.60. Gx, 27.20.+n, 25.30.Dh, 23.40.Hc

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Section: Results Of Calculationsupporting

confidence: 65%

“…Inelastic Ml form factor for the transition to the 3.563-MeV 0+ state of Li. Data are taken from[27].…”

mentioning

confidence: 99%

Neutron-proton halo structure of the 3.563-MeV0+state inLi6
Arai
¹
,
Suzuki
²
,
Varga
³

1995
Phys. Rev. C
78
5
30
1
View full text Add to dashboard Cite

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“…For an extraction of the form factor the data measured at 165 ± were normalized to elastic scattering taking into account the Coulomb distortion of the wave functions. Because of the rapid variation of the elastic scattering cross section as a function of the effective detection angle, the 180 ± measurements were normalized to the prominent M1 transition in 6 Li at 3.562 MeV where detailed form factor measurements are available [20].…”

mentioning

confidence: 99%

l-ForbiddenM1Transition inS32
Reitz
¹
,
Neumann-Cosel
²
,
Neumeyer
³

et al. 1999
Phys. Rev. Lett.
18
1
5
0
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The extremely weak l-forbidden 1d 3͞2 ! 2s 1͞2 magnetic dipole (M1) transition from the ground state of 32 S to a J p 1 1 state at E x 7.003 MeV was investigated by 165 ± and 180 ± electron scattering. The extracted strength of 0.0040͑5͒m 2 N represents the smallest B͑M1͒" value ever measured in electron scattering. A combined analysis with the isospin-analogous Gamow-Teller (GT) decays of the J p 1 1 ground states of 32 Cl and 32 P is performed. Empirical corrections of Brown and Wildenthal to the magnetic operators reasonably account for the data. Corrections derived from microscopic approaches are less successful pointing towards a fundamental, not yet understood problem in the description of the effective M1 and GT operators. [S0031-9007 (98)08207-6] PACS numbers: 25.30.Dh, 21.60.Cs, 23.20.Js, 27.30. + tThe phenomenon of quenching of the M1 and GamowTeller (GT) response in nuclei, i.e., the reduction of the experimentally observed strengths with respect to the best available model results, has attracted intense interest over the years (see, e.g., [1-6] and references therein). It has become clear that a large part of the reduction can be explained by tensor correlations induced by the renormalization of the transition strengths in (necessarily) truncated model spaces. However, there are also finite effects from non-nuclear degrees of freedom such as mesonic-exchange currents and excitations of nucleons to the D isobar. The different contributions can be incorporated by the introduction of effective M1 and GT operators [see Eqs. (1) and (2) below]. Spin, orbital, and tensor corrections to the operators for transitions in sd-shell nuclei have been derived from microscopic calculations of Arima et al. [2] and Towner and Khanna [7], as well as by Brown and Wildenthal [8] from empirical fits to a large body of data. Both methods agree quite well with each other except for the isovector M1 tensor corrections whose predicted magnitude is much smaller than the empirically found value.Allowed M1 and GT transitions are usually dominated by the spin strength, and the tensor corrections are weak. In contrast, l-forbidden transitions are mainly governed by the tensor part, thus providing experimental insight into this otherwise hardly accessible contribution. The term "l-forbidden" refers to a selection rule for the one-body operator of M1 or GT transitions which does not allow a change of the radial quantum number.The higher-order corrections to the l-forbidden transitions are theoretically expected to be dominated by D admixtures into the nuclear wave functions [2,7], and they are a unique observable in this respect. When scaled to the free-nucleon strength, the delta correction is expected to be essentially the same for the isovector M1 and GT operators. However, the analysis of the l-forbidden 1d 3͞2 ! 2s 1͞2 single-hole transitions in A 39 nuclei gives an order of magnitude larger M1 strength relative to the GT strength [9][10][11][12][13]. While this result contradicts the calculations [2,7] it can be well explained...

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“…The largest form factor in each case is shown as a point with its statistical error bars; the smaller form factor (if any) is shown by dashed (IA) and solid (IA+MEC) lines. Data are from Refs [3,4,29,[31][32][33]…”

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confidence: 99%

Microscopic Calculation ofL6iElastic and Transition Form Factors

1998

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Variational Monte Carlo wave functions, obtained from a realistic Hamiltonian consisting of the Argonne y 18 two-nucleon and Urbana-IX three-nucleon interactions, are used to calculate the 6 Li ground-state longitudinal and transverse form factors as well as transition form factors to the first four excited states. The charge and current operators include one-and two-body components, leading terms of which are constructed consistently with the two-nucleon interaction. The calculated form factors and radiative widths are in good agreement with available experimental data. [S0031-9007(98)07634-0] PACS numbers: 21.45. + v, 25.30.Bf, 25.30.Dh, 27.20. + n

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Electroexcitation of the 0+ (3.562 MeV) level of 6Li and its application to the reaction 6Li(γ, π+)6He

Cited by 73 publications

References 20 publications

Neutron-proton halo structure of the 3.563-MeV0+state inLi6
Arai
¹
,
Suzuki
²
,
Varga
³

1995
Phys. Rev. C
78
5
30
1
View full text Add to dashboard Cite

Neutron-proton halo structure of the 3.563-MeV0+state inLi6
Arai
¹
,
Suzuki
²
,
Varga
³

1995
Phys. Rev. C
78
5
30
1
View full text Add to dashboard Cite

l-ForbiddenM1Transition inS32
Reitz
¹
,
Neumann-Cosel
²
,
Neumeyer
³

et al. 1999
Phys. Rev. Lett.
18
1
5
0
View full text Add to dashboard Cite

Microscopic Calculation ofL6iElastic and Transition Form Factors

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Electroexcitation of the 0+ (3.562 MeV) level of 6Li and its application to the reaction 6Li(γ, π+)6He

Cited by 73 publications

References 20 publications

Neutron-proton halo structure of the 3.563-MeV0+state inLi6Arai1, Suzuki2, Varga3 1995Phys. Rev. C785301View full textAdd to dashboardCite

Neutron-proton halo structure of the 3.563-MeV0+state inLi6Arai1, Suzuki2, Varga3 1995Phys. Rev. C785301View full textAdd to dashboardCite

l-ForbiddenM1Transition inS32Reitz1, Neumann-Cosel2, Neumeyer3 et al. 1999Phys. Rev. Lett.18150View full textAdd to dashboardCite

Microscopic Calculation ofL6iElastic and Transition Form Factors

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About

Neutron-proton halo structure of the 3.563-MeV0+state inLi6
Arai
¹
,
Suzuki
²
,
Varga
³

1995
Phys. Rev. C
78
5
30
1
View full text Add to dashboard Cite

Neutron-proton halo structure of the 3.563-MeV0+state inLi6
Arai
¹
,
Suzuki
²
,
Varga
³

1995
Phys. Rev. C
78
5
30
1
View full text Add to dashboard Cite

l-ForbiddenM1Transition inS32
Reitz
¹
,
Neumann-Cosel
²
,
Neumeyer
³

et al. 1999
Phys. Rev. Lett.
18
1
5
0
View full text Add to dashboard Cite