Nuclear Core Polarization Effect on Beta Decay

Fujita, Jun–ichi; Fujii, Saburo; Ikeda, Kiyomi

doi:10.1103/physrev.133.b549

Cited by 59 publications

(77 citation statements)

References 22 publications

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“…For the 40 Ca nucleus, which is doubly shell-closed, there has been no 1 + state measured in the low-lying region [68]. Thus, 40 Ca is suitable to our rigidcore assumption.…”

Section: Camentioning

confidence: 99%

“…However, compared * E-mail: toishi@phy.hr † E-mail: npaar@phy.hr with the electric dipole (E1) and quadrupole (E2) modes [28][29][30][31][32][33][34], the knowledge on the pairing effect on magnetic modes, as well as on unnatural-parity states, is rather limited [10][11][12]20]. In studies of nuclear modes of excitation, the sum rules associated to the transition strength and energyweighted sum rules, represent an essential tool for the analyses of the excitations, not only as benchmark tests of the theoretical frameworks involved, but also to inspect the completeness of the experimental data [35][36][37][38][39][40][41][42][43][44][45][46][47][48]. Over the past decades, the analyses of the sum rules have been mandatory to validate theoretical approaches to describe various modes of excitation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic dipole excitation and its sum rule in nuclei with two valence nucleons

Oishi

Paar

2019

Phys. Rev. C

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Background: Magnetic dipole (M1) excitation is the leading mode of nuclear excitation by the magnetic field, which couples unnatural-parity states. Since the M1 excitation occurs mainly for open-shell nuclei, the nuclear pairing effect is expected to play a role. As expected from the form of operator, this mode may provide the information on the spin-related properties, including the spin component of dineutron and diproton correlations. In general, the sum rule for M1 transition strength has not been derived yet. Purpose: To investigate the M1 excitation of the systems with two valence nucleons above the closed-shell core, with pairing correlation included, and to establish the M1 sum rule that could be used to validate theoretical and experimental approaches. Possibility to utilize the M1 excitation as a tool to investigate the pairing correlation in medium is also discussed. Method: Three-body model, which consists of a rigid spherical core and two valence nucleons, is employed. Interactions for its two-body subsystems are phenomenologically determined in order to reproduce the two-body and three-body energies. We also derive the M1 sum rule within this three-body picture. Conclusion: The introduced M1 sum rule can be utilized as a benchmark for model calculations of M1 transitions in the systems with two valence nucleons. The total sum of the M1 transition strength is related with the coupled spin of valence nucleons in the open shell, where the pairing correlation is unnegligible. The three-body-model calculations for 18 O, 18 Ne, and 42 Ca nuclei demonstrate a significant effect of the pairing correlations on the low-lying M1 transitions. Therefore, further experimental studies of M1 transitions in those systems are on demand, in order to validate proposed sum rule, provide a suitable probe for the nuclear pairing in medium, as well as to optimize the pairing models.

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“…For the 40 Ca nucleus, which is doubly shell-closed, there has been no 1 + state measured in the low-lying region [68]. Thus, 40 Ca is suitable to our rigidcore assumption.…”

Section: Camentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetic dipole excitation and its sum rule in nuclei with two valence nucleons

Oishi

Paar

2019

Phys. Rev. C

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“…To this aim we neglect the l-forbidden terms in (2) and assume the constancy of the effective field when collective modes excited. If V(r) = const, then for nuclei where ΔE = (4/3) ε F (N − Z)/A > E ls 1 or x = ΔE/E ls > 1 the 1 The Fermi energy ε F ≈ 40 MeV energy difference ΔE G−A , normalized to the spin-orbital splitting E ls , is the following:…”

Section: Methods Of Calculationmentioning

confidence: 99%

“…The possible existence of spin-isospin resonance was first discussed in the works by Ikeda, Fujii, and Fujita in the middle of the 1960s as an attempt to explain the observed suppression effect of Gamow-Teller (GT) nuclear transitions [1][2][3]. They called this state the Gamow-Teller resonance (GTR), in analogy with analog resonance (AR) or Fermi resonance.…”

Section: Introductionmentioning

confidence: 99%

Charge-exchange resonances and restoration of the Wigner SU(4)-symmetry in heavy and superheavy nuclei

Lutostansky

Tikhonov

2016

EPJ Web of Conferences

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Abstract. Energies of the giant Gamow-Teller and analog resonances -E G and E A , respectively, -are calculated within the microscopic theory of finite Fermi system. The calculated energy difference ΔE G−A = E G − E A tends to zero with A in heavy nuclei indicating the restoration of Wigner SU(4)-symmetry. The calculated ΔE G−A values are in good agreement with the experimental data. The average deviation is 0.30 MeV for the 33 considered nuclei where experimental data are available. The ΔE G−A values are investigated for very heavy and superheavy nuclei up to the mass number A = 290. Using the experimental data for the analog resonance energies, the isotopic dependence of the Coulomb energy differences for neighboring isobars are analyzed within the SU(4)-approach for more than 400 nuclei in the mass number range of A = 3 − 244. The Wigner SU(4)-symmetry restoration for heavy and superheavy nuclei is confirmed. It is shown that the restoration of SU(4)-symmetry does not contradict the possibility of the existence of the "island of stability" in the region of superheavy nuclei.

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“…The famous examples include the CE excitations by the (p, n) as well as ( 3 He, t) reactions. In addition, one remarkable advantage in studies on GT modes is the existence of the Ikeda-Fujii-Fujita sum rule [31,32]. This rule has provided an essential constraint to validate studies of GT resonances and spin-isospin properties in nuclei [33][34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Symmetry breaking of Gamow-Teller and magnetic-dipole transitions and its restoration in calcium isotopes

Oishi,

Ravlic,

Paar

2022

Preprint

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Nuclear magnetic-dipole (M1) and Gamow-Teller (GT) transitions provide insight into the spinisospin properties of atomic nuclei. By considering them as unified spin-isospin transitions, the M1/GT transition strengths and excitation energies are subject to isobaric-analog symmetry. The excitation properties associated to the M1/GT symmetry need to be clarified within consistent theoretical approach. In this work, the relationship between the M1 and GT transitions in Ca isotopes is investigated in a unified framework based on the relativistic energy-density functional (REDF) with point-coupling interactions, using the relativistic quasi-particle random-phase approximation (RQRPA). It is shown that the isovector-pseudovector (IV-PV) residual interaction affects these transitions. The symmetry of M1 and giant-GT transitions can be disrupted by this interaction in closed-shell nuclei. In open-shell Ca isotopes, the proton-neutron pairing in the residual RQRPA interaction also plays a role in GT transitions. Due to the interplay between these interactions, the M1/GT symmetry can be restored especially in the 42 Ca nucleus, i.e., the giant-GT strength can become comparable to that of the M1 mode in terms of the unified spin-isospin transitions by fixing the PN-pairing strength so as to reproduce the experimental low-lying GT-excitation energies. The mirror symmetry of both M1 and GT transitions is also demonstrated for open-shell mirror partners, 42 Ca and 42 Ti. Further improvements are required to achieve more accurate simultaneous reproduction of M1 and GT-transition energies in the REDF framework.

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Nuclear Core Polarization Effect on Beta Decay

Cited by 59 publications

References 22 publications

Magnetic dipole excitation and its sum rule in nuclei with two valence nucleons

Magnetic dipole excitation and its sum rule in nuclei with two valence nucleons

Charge-exchange resonances and restoration of the Wigner SU(4)-symmetry in heavy and superheavy nuclei

Symmetry breaking of Gamow-Teller and magnetic-dipole transitions and its restoration in calcium isotopes

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