The role of tensor force in heavy-ion fusion dynamics

Guo, Lu; Simenel, C.; Shi, Long; Chong, Yu

doi:10.1016/j.physletb.2018.05.066

Cited by 55 publications

(55 citation statements)

References 65 publications

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“…2.4). The largest differences in cross section were seen by varying the symmetry energy, as expected, with the rather modest range of J = 28-34 MeV (being consistent with observation [ Figure 12: Cross-sections with different tensor forces, from [141].…”

Section: Variation Of Nuclear Matter Propertiessupporting

confidence: 87%

“…Upper panel shows fusion barrier for selection of Skyrme-tensor forces using the Frozen HF (FHF) approximation, or full TDHF, compared with the experimental value[142]. The lower panel shows collective quadrupole (2 + ) and octupole (3 − ) states which contribute to the lowering of the barrier in TDHF compared to FHF, with the lower energy collective states correlating with the stronger reduction in the barrier height in TDHF.Figure from[141] …”

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confidence: 99%

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Low-energy heavy-ion reactions and the Skyrme effective interaction

Stevenson

Barton

2019

Progress in Particle and Nuclear Physics

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The Skyrme effective interaction, with its multitude of parameterisations, along with its implementation using the static and time-dependent density functional (TDHF) formalism have allowed for a range of microscopic calculations of low-energy heavy-ion collisions. These calculations allow variation of the effective interaction along with an interpretation of the results of this variation informed by a comparison to experimental data. Initial progress in implementing TDHF for heavy-ion collisions necessarily used many approximations in the geometry or the interaction. Over the last decade or so, the implementations have overcome all restrictions, and studies have begun to be made where details of the effective interaction are being probed. This review surveys these studies in low energy heavy-ion reactions, finding significant effects on observables from the form of the spin-orbit interaction, the use of the tensor force, and the inclusion of time-odd terms in the density functional.Heavy-ion collisions combine the rich dynamics of a many-body out-of-equilibrium open quantum system with the complexities of the residual part of the strong interaction which leaks out of the small, but neither fundamental or point-like, nucleons, causing them to stick loosely together some of the time, and to fall apart at others. Understanding heavy-ion reactions across all energy scales is necessary to understand stellar nucleosynthesis [1], the synthesis of superheavy nuclei [2,3], the properties of nuclear matter [4][5][6], the QCD phase diagram [7,8] as well as the understanding of reaction mechanisms themselves [9][10][11][12][13].Among the theoretical techniques used to study heavy-ion reactions, methods based on timedependent Hartree-Fock have recently achieved the status of having sufficiently mature implementations free of limiting approximations, and running at a suitable speed, such that systematically varying the effective interaction in the calculations is possible. It is such studies that form the main subject of the present review. The practical implementations, using the Skyrme interaction, are in some sense parameter-free, in that one has a framework using an effective interaction fitted to ground state data and nuclear matter properties, with no further adjustment to dynamics. Structure and reaction effects are together determined self-consistently from the interaction, subject to the approximations of the mean-field and one gives no further adjustment. In another sense, the variation among the sets of available effective interactions are parameters of the calculations. We attempt to summarise here what has been learnt from exploring different Skyrme force parameterisations within low-energy heavy-ion reaction calculations.Overlapping this subject area are other recent review articles, to which the reader is referred: A review in which extensive coverage of theoretical approaches to dynamics of heavy-ion collisions in TDHF and its extensions is presented by Simenel and Umar [14]. This review extensively covers the...

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Section: Variation Of Nuclear Matter Propertiessupporting

confidence: 87%

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confidence: 99%

Low-energy heavy-ion reactions and the Skyrme effective interaction

Stevenson

Barton

2019

Progress in Particle and Nuclear Physics

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“…The spin-orbit coupling is known to play an important role in energy dissipation processes in heavy-ion reactions [108][109][110][111]. The effects of the tensor term on nuclear dynamics were also investigated recently [102,[112][113][114][115]. TDHF enables us to study rich and complex physics of low-energy heavy-ion reactions from nucleonic degrees of freedom.…”

Section: The Tdhf Theorymentioning

confidence: 99%

TDHF Theory and Its Extensions for the Multinucleon Transfer Reaction: A Mini Review

Sekizawa

2019

Front. Phys.

105

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Time-dependent Hartree-Fock (TDHF) theory has been a powerful tool in describing a variety of complex nuclear dynamics microscopically without empirical parameters. In this contribution, recent advances in nuclear dynamics studies with TDHF and its extensions are briefly reviewed, along the line with the study of multinucleon transfer (MNT) reactions. The latter lies at the core of this Research Topic, whose application for production of extremely neutron-rich nuclei has been extensively discussed in recent years. Having in mind the ongoing theoretical developments, it is envisaged how microscopic theories may contribute to the future MNT study. 1 Here a local EDF (like Skyrme) has been assumed, which makes the TDHF equations (1) local in space, as it is currently used in most of practical applications. In general, E = E(r)dr is composed of various local densities, ξ ≡ {ρ, τ, . . . }, and the TDHF equations (1)In such a case, the single-particle Hamiltonian can have spin dependence as well as differential operators (for the explicit form, see, e.g., Refs. [27][28][29]).

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“…In Ref. [42], how these dynamical effects affect the fusion barriers heights, computed directly from TDHF, have been investigated to study the role of tensor force on above-barrier fusion dynamics. We note that in Ref.…”

Section: Resultsmentioning

confidence: 99%

“…Quantum effects are considered, which is essential for the manifestation of shell effects during the collision dynamics. Recently, the effect of the tensor force in heavy-ion collisions has been studied using direct TDHF calculations [38][39][40][41][42]. Furthermore, the TDHF approach provides a deeper understanding of nuclear dynamics, as seen in recent applications to fusion [32][33][34][35][36][37][43][44][45][46][47][48], quasifission [49][50][51][52][53], transfer reactions [54][55][56][57][58][59][60][61], fission [62][63][64][65][66][67], and deep inelastic collisions [39][40][41][68][69][70][71][72][73][74].…”

Section: Introductionmentioning

confidence: 99%

Influence of the tensor force on the microscopic heavy-ion interaction potential

2018

Self Cite

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Background: The tensor interaction is known to play an important role in the nuclear structure studies of exotic nuclei. However, most microscopic studies of low-energy nuclear reactions neglect the tensor force, resulting in a lack of knowledge concerning the effect of the tensor force on heavy-ion collisions. An accurate description of the heavy-ion interaction potential is crucial for understanding the microscopic mechanisms of heavy-ion fusion dynamics. Furthermore, the building blocks of the heavy-ion interaction potential in terms of the ingredients of the effective nucleon-nucleon interaction provides the physical underpinnings for connecting the theoretical results with experiment. The tensor force has never been incorporated for calculating the nucleusnucleus interaction potential. Purpose: The theoretical study of the influence of the tensor force on heavy-ion interaction potentials is required to further our understanding of the microscopic mechanisms entailed in fusion dynamics. Method: The full Skyrme tensor force is implemented into the static Hartree-Fock and dynamic densityconstrained time-dependent Hartree-Fock (DC-TDHF) theory to calculate both static (frozen density) and dynamic microscopic interaction potentials for reactions involving exotic and stable nuclei. Results: The static potentials are found to be systematically higher than the dynamical results, which are attributed to the microscopic dynamical effects included in TDHF. We also show that the dynamical potential barriers vary more significantly by the inclusion of tensor force than the static barriers. The influence of isoscalar and isovector tensor terms is also investigated with the TIJ set of forces. For light systems, the tensor force is found to have an imperceptible effect on the nucleus-nucleus potential. However, for medium and heavy spinunsaturated reactions, the potentials may change from a fraction of an MeV to almost 2 MeV by the inclusion of tensor force, indicating a strong impact of the tensor force on sub-barrier fusion. Conclusions: The tensor force could indeed play a large role in the fusion of nuclei, with spin-unsaturated systems seeing a systematic increase in ion-ion barrier height and width. This fusion hindrance is partly due to static, ground state effects from the inclusion of the tensor force, though additional hindrance appears when studying nuclear dynamics.where H 0 is the simplified functional used in the Sky3D TDHF code [82] and most TDHF calculations. The terms containing the coupling constants A arise from the Skyrme central

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The role of tensor force in heavy-ion fusion dynamics

Cited by 55 publications

References 65 publications

Low-energy heavy-ion reactions and the Skyrme effective interaction

Low-energy heavy-ion reactions and the Skyrme effective interaction

TDHF Theory and Its Extensions for the Multinucleon Transfer Reaction: A Mini Review

Influence of the tensor force on the microscopic heavy-ion interaction potential

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