arXiv subjects

Yoritaka Iwata

Publications and source records attributed to Yoritaka Iwata.

43 records · Page 3Linked to original sources

arXiv2012

Synthesis of thin-long heavy nuclei in ternary collisions

We illustrate the formation of a thin-long structure of heavy nuclei by three-nucleus simultaneous collisions within time-dependent density functional theory. The impact parameter dependence for such formation is systematically demonstrated through clarifications of the difference between binary and ternary collision events. A new method for producing thin-long heavy nuclei in the laboratory is suggested, as well as the possible formation of the thin-long structure in hot dense matter such as that encountered in core collapse supernovae.

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arXiv2012

Fission Dynamics of Compound Nuclei

Collisions between $^{248}$Cm and $^{48}$Ca are systematically investigated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, deep-inelastic and quasi-fission events are expected to appear. In this paper, possible fission dynamics of compound nuclei is presented.

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arXiv2012

Evaporation Prescription for Time-Dependent Density Functional Calculations

Collisions between $^{248}$Cm and $^{48}$Ca are systematically calculated by time-dependent density functional calculations with evaporation prescription. Depending on the incident energy and impact parameter, fusion, fusion-fission, and quasi-fission events are expected to appear. In this paper, the evaporation prescription is introduced, which is expected to be rather important to heavy-ion reactions producing superheavy nuclei, where the heavier total mass can be related to the higher total excitation energy.

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arXiv2012

Zero Sound Propagation in Femto-Scale Quantum Liquids

Charge equilibration has been recognized as a dominant process at the early stage of low-energy heavy-ion reactions. The production of exotic nuclei is suppressed under the appearance of charge equilibration, in which the proton-neutron ratios of the final reaction products are inevitably averaged. Therefore charge equilibration plays one of the most crucial roles in the synthesis of chemical elements. Focusing on how and when the charge equilibration takes place, the zero-sound propagation in femto-scale quantum liquids is explained.

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arXiv2012

Phase diagram of dilute cosmic matter

Enhancement of nuclear pasta formation due to multi-nucleus simultaneous collision is presented based on time-dependent density functional calculations with periodic boundary condition. This calculation corresponds to the situation with density lower than the known low-density existence limit of the nuclear pasta phase. In order to evaluate the contribution from three-nucleus simultaneous collisions inside the cosmic matter, the possibility of multi-nucleus simultaneous collisions is examined by a systematic Monte-Carlo calculation, and the mean free path of a nucleus is obtained. Consequently the low-density existence limit of the nuclear pasta phase is formed to be lower than believed up to now.

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arXiv2011

Enhanced Tensor-Force Contribution in Collision Dynamics

The tensor and spin-orbit forces contribute essentially to the formation of the spin mean field, and give rise to the same dynamical effect, namely spin polarization. In this paper, based on time-dependent density functional calculations, we show that the tensor force, which usually acts like a small correction to the spin-orbit force, becomes more important in heavy-ion reactions and the effect increases with the mass of the system.

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arXiv2010

Suppression of Charge Equilibration leading to the Synthesis of Exotic Nuclei

Charge equilibration between two colliding nuclei can take place in the early stage of heavy-ion collisions. A basic mechanism of charge equilibration is presented in terms of the extension of single-particle motion from one nucleus to the other, from which the upper energy-limit of the bombarding energy is introduced for significant charge equilibration at the early stage of the collision. The formula for this limit is presented, and is compared to various experimental data. It is examined also by comparison to three-dimensional time-dependent density functional calculations. The suppression of charge equilibration, which appears in collisions at the energies beyond the upper energy-limit, gives rise to remarkable effects on the synthesis of exotic nuclei with extreme proton-neutron asymmetry.

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