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We address the consequences of strong tensor terms in the local energy density functional, resulting from fits to the f5/2 - f7/2 splittings in 40Ca , 48Ca , and 56Ni . In this study, we focus on the tensor contribution to the nuclear binding energy. In particular, we show that it exhibits an interesting topological feature closely resembling that of the shell correction. We demonstrate that in the extreme single-particle scenario at spherical shape, the tensor contribution shows tensorial magic numbers equal to N( Z) = 14 , 32, 56, and 90, and that this structure is smeared out due to configuration mixing caused by pairing correlations and migration of proton/neutron sub-shells with neutron/proton shell filling. Based on a specific Skyrme-type functional SLy4T, we show that the proton tensorial magic numbers shift with increasing neutron excess to Z = 14 , 28, and 50. [ABSTRACT FROM AUTHOR]

: A number of previously unobserved γ-rays emitted from the neutron-deficient nuclide 171Pt have been identified using the recoil decay tagging technique. The level scheme has been updated using information from γ-γ coincidences and angular distribution measurements. To further confirm the assignments of the γ-rays to 171Pt, the events were correlated with the alpha-decay of the daughter nucleus 167Os. [ABSTRACT FROM AUTHOR]

The empirical pairing gaps derived from four different odd–even mass staggering formulas are compared. By performing single- j shell and multi-shell seniority model calculations as well as by using the standard HFB approach with Skyrme force we show that the simplest three-point formula Δ C ( 3 ) ( N ) = 1 2 [ B ( N , Z ) + B ( N − 2 , Z ) − 2 B ( N − 1 , Z ) ] can provide a good measure of the neutron pairing gap in even- N nuclei. It removes to a large extent the contribution from the nuclear mean field as well as contributions from shell structure details. It is also less contaminated by the Wigner effect for nuclei around N = Z . We also show that the strength of Δ C ( 3 ) ( N ) can serve as a good indication of the two-particle spatial correlation in the nucleus of concern and that the weakening of Δ C ( 3 ) ( N ) in some neutron-rich nuclei indicates that the di-neutron correlation itself is weak in these nuclei. [ABSTRACT FROM AUTHOR]

We analyze the α-decay fine structure to excited 02+ states in Hg and Rn isotopes. These states are described as minima in the potential energy surface (PES) provided by the standard deformed Woods-Saxon plus pairing approach. We also investigate a decay from the excited state P(02+) in the parent nucleus by evaluating the corresponding hindrance factor (HF). By analyzing the experimental HF's we find the remarkable property that the ground and excited states D(01+) and D(02+) in the daughter nuclei are occupied with almost equal probabilities if there is no excited P(0+) states in the parent nucleus. Moreover, if there exists an excited state P(02+) then the occupation probability of this state is 25%. [ABSTRACT FROM AUTHOR]

Recent B(E2;0g.s.+→21+) measurements in light tin isotopes have revealed surprisingly large values relative to standard shell model predictions, generating an unexpected asymmetry in the B(E2) values with respect to the neutron midshell. This effect has triggered various speculations as to its origin, such as a possible weakening of the N,Z=50 shell closure. Here we present new shell model calculations to investigate the origin of the observed asymmetric character of the B(E2) values in the tin isotopes. By including the effects of the neutron g9/2 orbital below the N=50 shell gap it is shown that Pauli blocking effects may play an important role near the N=50 shell closure. A new set of single-particle energies and monopole interactions, fitted to the experimental data in the region, together with the isospin-dependent effective charge suggested by Bohr and Mottelson is shown to reproduce the experimental transition rate values in the Sn isotopic chain. [ABSTRACT FROM AUTHOR]

Abstract: The recently proposed spin-aligned neutron–proton pair coupling scheme is studied within a non-orthogonal basis in term of the multistep shell model. This allows us to identify simultaneously the roles played by other configurations such as the normal pairing term. The model is applied to four-, six- and eight-hole nuclei below the core 100Sn. [Copyright &y& Elsevier]

Excited states in the odd-odd neutron deficient nucleus 162Ta (Z = 73, N = 89) have been studied for the first time. The gamma spectroscopy analysis using y - y - y coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration πh11/2[514]9/2⊗νi13/2[660]1/2 based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a y-soft minimum at &bgr;2 ≈ 0.16 and γ ≈ 6° . The crossing of the signature partners observed in heavier (N ≽ 91) odd-odd nuclides in this mass region is found to be absent at N = 89. This might be correlated with a change in S-band structure above the paired band crossing at these neutron numbers. [ABSTRACT FROM AUTHOR]

Shell-model calculations using realistic interactions reveal that the ground and low-lying yrast states of the N=Z nucleus 92/46Pd are mainly built upon isoscalar neutron-proton pairs, each carrying the maximum angular momentum J=9 allowed by the shell 0g9/2, which is dominant in this nuclear region. This structure is different from that found in the ground and low-lying yrast states of all other even-even nuclei studied so far. The low-lying spectrum of excited states generated by such correlated neutron-proton pairs has two distinctive features: (i) the levels are almost equidistant at low energies and (ii) the transition probability I→I-2 is approximately constant and strongly selective. This unique mode is shown to replace normal isovector pairing as the dominant coupling scheme in N=Z nuclei approaching the doubly magic nucleus 100Sn. [ABSTRACT FROM AUTHOR]