Microscopic calculation and local approximation of the spatial dependence of the pairing field with bare and induced interactions

Pastore, Alessandro; Barranco, F.; Broglia, R. A.; Vigezzi, E.

doi:10.1103/physrevc.78.024315

Cited by 81 publications

(199 citation statements)

References 27 publications

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“…For example, in nuclear matter the Sly4 effective mass is equal to m * = 0.7m. So a small value of the effective mass leads to a strong suppression of the gap value to BCS = 0.7 MeV in [2] or BCS = 1.04 MeV in [3]. In both cases, the too small value of the gap was explained by invoking various many-body corrections to the BCS approximation.…”

Section: Introductionmentioning

confidence: 99%

“…It should be noticed that the main difficulty of the direct method to solve the nuclear pairing problem comes from the rather slow convergence of the sums over intermediate states λ in the gap equation, because of the short range of the free NN force. This, evidently, was the main reason why the Milan group limited their investigations [1][2][3] to only the nucleus 120 Sn. To avoid the slow convergence, the authors of Refs.…”

Section: Introductionmentioning

confidence: 99%

“…In Ref. [3], the contribution of the induced interaction caused by exchange of the high-lying in-volume excitations was added also; the sum again was equal to 1.4 MeV. Thus, the calculations of Refs.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the calculations of Refs. [2,3] showed that the effects of an effective mass m * = m and of many-body corrections to the BCS theory are necessary to explain the difference of ( BCS − exp ). In addition, their contributions are of different sign and partially compensate each other.…”

Section: Introductionmentioning

confidence: 99%

“…In Refs. [2,3] the basis was enlarged from E max = 600 MeV in [1] to E max = 800 MeV, and the effective mass m * = m was introduced into the gap equation. The new basis was calculated within the Skyrme-HartreeFock method with the Sly4 force [4], which makes the effective mass m * (r) coordinate dependent and essentially different from the bare one.…”

Section: Introductionmentioning

confidence: 99%

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Phonon effects on the double mass differences in magic nuclei

et al. 2016

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Odd-even double mass differences (DMDs) of magic nuclei are found within an approach starting from the free NN interaction, accounting for particle-phonon coupling (PC) effects. We consider three PC effects: the phonon-induced effective interaction, the renormalization of the "ends" due to the pole PC contribution to the nucleon mass operator, and the change of the single-particle energies. The perturbation theory in g 2 L , where g L is the vertex of the creation of the L-multipole phonon, is used for PC calculations. PC corrections to single-particle energies are found with an approximate accounting for the tadpole diagram. Results for magic 40,48 Ca, 56,78 Ni, 100,132 Sn, and 208 Pb nuclei are presented. For the lighter part of this set of nuclei, from 40 Ca to 56 Ni, the cases divide approximately in half, between those where the PC corrections to DMD values are in good agreement with the data and the ones with the opposite result. In the major part of the cases of worsening description of DMD, a poor applicability of the perturbation theory for the induced interaction is the most probable reason of the phenomenon. For intermediate nuclei, 78 Ni and 100 Sn, there are no sufficiently accurate data on masses of nuclei necessary for finding DMD values. Finally, for heavier nuclei, 132 Sn and 208 Pb, PC corrections always result in better agreement with experiment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phonon effects on the double mass differences in magic nuclei

et al. 2016

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From low-momentum interactions to nuclear structure

Bogner

Furnstahl

Schwenk

2010

Progress in Particle and Nuclear Physics

552

856

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We present an overview of low-momentum two-nucleon and many-body interactions and their use in calculations of nuclei and infinite matter. The softening of phenomenological and effective field theory (EFT) potentials by renormalization group (RG) transformations that decouple low and high momenta leads to greatly enhanced convergence in few- and many-body systems while maintaining a decreasing hierarchy of many-body forces. This review surveys the RG-based technology and results, discusses the connections to chiral EFT, and clarifies various misconceptions.Comment: 76 pages, 57 figures, two figures updated, published versio

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Observation of the proton emitter $${}_{\,57}^{116}$$La59

et al. 2022

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The quantum tunneling and emission of a single constituent nucleon provide a beautifully simple and unique window into the complex properties of atomic nuclei at the extreme edge of nuclear existence. In particular, for odd-odd proton emitting nuclides, the associated decay energy and partial half-life can be used to probe the correlations between the valence neutrons and protons which have been theoretically predicted to favour a new type of nuclear superfluidity, isoscalar neutron-proton pairing, for which the experimental “smoking gun" remains elusive. In the present work, proton emission from the lanthanum isotope $${}_{\,57}^{116}$$ 57 116 La59, 23 neutrons away from the only stable isotope $${}_{\,57}^{139}$$ 57 139 La82, is reported. 116La nuclei were synthesised in the fusion-evaporation reaction 58Ni(64Zn, p5n)116La and identified via their proton radioactivity using the mass spectrometer MARA (Mass Analysing Recoil Apparatus) and the silicon detectors placed at its focal plane. Comparisons of the measured proton energy (Ep = 718 ± 9 keV) and half-life (T1/2 = 50 ± 22 ms) with values calculated using the Universal Decay Law approach indicate that the proton is emitted with an orbital angular momentum l = 2 and that its emission probability is enhanced relative to its closest, less exotic, odd-even lanthanum isotope ($${}_{\,57}^{117}$$ 57 117 La60) while the proton-emission Q-value is lower. We propose this to be a possible signature for the presence of strong neutron-proton pair correlations in this exotic, neutron deficient system. The observations of γ decays from isomeric states in 116La and 117La are also reported.

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Microscopic calculation and local approximation of the spatial dependence of the pairing field with bare and induced interactions

Cited by 81 publications

References 27 publications

Phonon effects on the double mass differences in magic nuclei

Phonon effects on the double mass differences in magic nuclei

From low-momentum interactions to nuclear structure

Observation of the proton emitter $${}_{\,57}^{116}$$La59

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