Neutron-proton pairing correction in the extended isovector and isoscalar pairing model

2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Feng Pan ◽  
Yingwen He ◽  
Yingxin Wu ◽  
Yu Wang ◽  
Kristina D. Launey ◽  
...  
Keyword(s):  
Pairing Model ◽  
Proton Pairing

scholarly journals np-Pair Correlations in the Isovector Pairing Model

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1405
Author(s):  
Feng Pan ◽  
Yingwen He ◽  
Lianrong Dai ◽  
Chong Qi ◽  
Jerry P. Draayer
Keyword(s):  
Binding Energy ◽  
Occupation Number ◽  
Mean Field ◽  
Energy Difference ◽  
Binding Energies ◽  
Pair Correlations ◽  
Isospin Symmetry Breaking ◽  
Pairing Model ◽  
Proton Pairing ◽  
Spin Basis

A diagonalization scheme for the shell model mean-field plus isovector pairing Hamiltonian in the O(5) tensor product basis of the quasi-spin SUΛ(2) ⊗ SUI(2) chain is proposed. The advantage of the diagonalization scheme lies in the fact that not only can the isospin-conserved, charge-independent isovector pairing interaction be analyzed, but also the isospin symmetry breaking cases. More importantly, the number operator of the np-pairs can be realized in this neutron and proton quasi-spin basis, with which the np-pair occupation number and its fluctuation at the J = 0+ ground state of the model can be evaluated. As examples of the application, binding energies and low-lying J = 0+ excited states of the even–even and odd–odd N∼Z ds-shell nuclei are fit in the model with the charge-independent approximation, from which the neutron–proton pairing contribution to the binding energy in the ds-shell nuclei is estimated. It is observed that the decrease in the double binding-energy difference for the odd–odd nuclei is mainly due to the symmetry energy and Wigner energy contribution to the binding energy that alter the pairing staggering patten. The np-pair amplitudes in the np-pair stripping or picking-up process of these N = Z nuclei are also calculated.

scholarly journals Evidence of a sudden increase in the nuclear size of proton-rich silver-96

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Reponen ◽  
R. P. de Groote ◽  
L. Al Ayoubi ◽  
O. Beliuskina ◽  
M. L. Bissell ◽  
...  
Keyword(s):  
Charge Radius ◽  
Density Functional ◽  
Theory Development ◽  
Density Functional Theory Calculations ◽  
Neutron Number ◽  
Nuclear Charge Radius ◽  
Sudden Increase ◽  
Nuclear Theory ◽  
Charge Radii ◽  
Proton Pairing

AbstractUnderstanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus 100Sn, where the near-equal number of protons (Z) and neutrons (N) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the N = 50 magic neutron number in the silver isotopic chain with the measurement of the charge radius of 96Ag (N = 49). The results provide a challenge for nuclear theory: calculations are unable to reproduce the pronounced discontinuity in the charge radii as one moves below N = 50. The technical advancements in this work open the N = Z region below 100Sn for further optical studies, which will lead to more comprehensive input for nuclear theory development.

scholarly journals Investigating neutron-proton pairing in sd -shell nuclei via (p,He3) and (He3,p) transfer reactions

2017 ◽  
Vol 96 (2) ◽  
Author(s):  
Y. Ayyad ◽  
J. Lee ◽  
A. Tamii ◽  
J. A. Lay ◽  
A. O. Macchiavelli ◽  
...  
Keyword(s):  
Transfer Reactions ◽  
Proton Pairing

New magic nuclei and neutron-proton pairing

2008 ◽  
Vol 71 (7) ◽  
pp. 1250-1254 ◽  
Author(s):  
I. N. Boboshin
Keyword(s):  
Proton Pairing

scholarly journals Exact solution of spherical mean-field plus special orbit-dependent non-separable pairing model with multi non-degenerate j-orbits

2019 ◽  
Vol 795 ◽  
pp. 165-171 ◽  
Author(s):  
Feng Pan ◽  
Dan Zhou ◽  
Yingwen He ◽  
Siyu Yang ◽  
Yunfeng Zhang ◽  
...  
Keyword(s):  
Exact Solution ◽  
Mean Field ◽  
Spherical Mean ◽  
Pairing Model

scholarly journals Onset of superconductivity and retention of magnetic fields in cooling neutron stars

2017 ◽  
Vol 13 (S337) ◽  
pp. 213-216
Author(s):  
Wynn C. G. Ho ◽  
Nils Andersson ◽  
Vanessa Graber
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Minimum Energy ◽  
Meissner Effect ◽  
Energy Conditions ◽  
Field Diffusion ◽  
Neutron Star Cooling ◽  
Proton Pairing

AbstractA superconductor of paired protons is thought to form in the core of neutron stars soon after their birth. Minimum energy conditions suggest that magnetic flux is expelled from the superconducting region due to the Meissner effect, such that the neutron star core retains or is largely devoid of magnetic fields for some nuclear equation of state and proton pairing models. We show via neutron star cooling simulations that the superconducting region expands faster than flux is expected to be expelled because cooling timescales are much shorter than timescales of magnetic field diffusion. Thus magnetic fields remain in the bulk of the neutron star core for at least 106 − 107yr. We estimate the size of flux free regions at 107yr to be ≲ 100m for a magnetic field of 1011G and possibly smaller for stronger field strengths.

scholarly journals The competition of tensor interaction and neutron-proton pairing in the beta-decay of the neutron-rich isotopes

2019 ◽  
Vol 201 ◽  
pp. 09011
Author(s):  
E. O. Sushenok ◽  
A. P. Severyukhin ◽  
N. N. Arsenyev ◽  
I. N. Borzov
Keyword(s):  
Random Phase Approximation ◽  
Neutron Emission ◽  
Random Phase ◽  
Tensor Interaction ◽  
Wave Functions ◽  
Skyrme Interaction ◽  
Quasiparticle Random Phase Approximation ◽  
Cd Isotopes ◽  
Neutron Rich Isotopes ◽  
Proton Pairing

The effects of the residual interaction in the particle-particle channel on β-decay characteristics and the multi-neutron emission probabilities in the β-decay of 126,128,130,132Cd are studied within the quasiparticle random phase approximation with the Skyrme interaction. The coupling between one-and two-phonon terms in the wave functions of the low-energy 1+ states of the daughter nuclei is taken into account. It is shown that the inclusion of the spin-isospin interaction in the particle-particle channel leads to the reduction of half-lives and redistribution of one-and two-neutron emission probabilities. The competition of tensor interaction and neutron-proton pairing in the β-decay characteristics of the neutron-rich Cd isotopes is discussed.

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