Heavy-isotope production in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Xe</mml:mi><mml:mprescripts /><mml:none /><mml:mn>136</mml:mn></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mmultiscripts><mml:mi>Pb</mml:mi><mml:mprescripts /><mml:none /><mml:mn>208</mml:mn></mml:mmultiscripts></mml:mrow></mml:math>
 collisions at 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>E</mml:mi><mml:mrow><mml:mi mathvariant="normal">c</mml

Ayık, S.; Yılmaz, O.; Yilmaz, B.; Umar, A. S.

doi:10.1103/physrevc.100.044614

Cited by 23 publications

(7 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, this approach appears to have a technical problem in describing dispersions of one-body observables in asymmetric systems [53]. As seen from recent publications [67][68][69][70][71], the quantal diffusion description for multinucleon exchanges based on the stochastic mean-field (SMF) approach provides very good description for multinucleon transfer mechanism, which is applicable for asymmetric reactions as well.…”

Section: Discussionmentioning

confidence: 99%

“…The approach was successfully applied to 48 Ca+ 238 U [67], 58,60 Ni+ 60 Ni [68], 136 Xe+ 208 Pb [69,70], and 48 Ca+ 208 Pb [71] systems. We mention here that the SMF approach has also been applied in other contexts such as spinordal instabilities of nuclear matter [72][73][74][75], symmetry breaking [76], Fermionic Hubbard clusters [77], as well as nuclear fission [78].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Quantal diffusion approach for multinucleon transfer processes in the $^{58,64}$Ni+$^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

Sekizawa,

Ayik

2020

Preprint

View full text Add to dashboard Cite

Background: In recent years, substantial efforts have been made for the study of multinucleon transfer reactions at energies around the Coulomb barrier both experimentally and theoretically, aiming at the production of unknown neutron-rich heavy nuclei. It is crucial to provide reliable theoretical predictions based on microscopic theories with sufficient predictive power.Purpose: This paper aims to clarify the applicability of the quantal diffusion approach based on the stochastic mean-field (SMF) theory for multinucleon transfer processes. Isotope production cross sections are evaluated for the reactions of 64 Ni+ 208 Pb at Ec.m. = 268 MeV and 58 Ni+ 208 Pb at Ec.m. = 270 MeV and are compared with available experimental data. Methods: Three-dimensional time-dependent Hartree-Fock (TDHF) calculations are carried out for a range of initial orbital angular momenta with Skyrme SLy4d functional. Quantal diffusion equations, derived based on the SMF theory, for variances and covariance of neutron and proton numbers of reaction products are solved, with microscopic drift and diffusion coefficients obtained from the time evolution of occupied single-particle orbitals in TDHF. Secondary deexcitation processes, both particle evaporation and fission, are simulated by a statistical compound-nucleus deexcitation model, GEMINI++.Results: Dynamics of a fast isospin equilibration process followed by a slow drift towards the mass symmetry are commonly observed, as expected. Various reaction outcomes are evaluated, including average mass and charge numbers of reaction products, total kinetic energy loss (TKEL), scattering angle, contact time, and production cross sections for primary and secondary products. By comparing with the experimental data, we find that SMF and TDHF quantitatively reproduce experimental data for few-nucleon-transfer channels around the average values. In contrast, for many-nucleon-transfer channels, we find that the SMF approach provides much better description of the experimentally measured isotopic distributions. The results underline the importance of beyond mean-field effects, especially one-body (mean-field) fluctuations and correlations, in describing multinucleon transfer processes. Moreover, through a combined analysis of SMF with a statistical model, GEMINI++, we find a significant contribution of transfer-induced fission, which is consistent with the experimental observation. In some cases, the SMF approach overestimates the isotopic width, requiring further improvements of the theoretical description. Possible ways to improve the description are discussed. Conclusions:The SMF approach is designed to describe the quantum many-body problem according to a classical ensemble of mean-field trajectories, taking into account part of many-body correlations in the description. As it requires feasible computational costs comparable to the ordinary TDHF approach, together with further model improvements, it will be a promising tool to search for optimal reaction conditions to produce yet-unknown neutron-r...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantal diffusion approach for multinucleon transfer processes in the $^{58,64}$Ni+$^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

Sekizawa,

Ayik

2020

Preprint

View full text Add to dashboard Cite

show abstract

“…To obtain such quantities one needs to go beyond standard TDHF and consider the fluctuations around the TDHF meanfield trajectory using techniques like the stochastic mean-field theory (SMF) [108,109] or TDRPA [71]. Both of these approaches have been used to investigate MNT and fragment production [72][73][74][75][76][77][110][111][112][113][114].…”

Section: Formalism: Tdhf and Tdrpamentioning

confidence: 99%

Microscopic predictions for the production of neutron-rich nuclei in the reaction Yb176 + Yb176
Godbey
¹
,
Simenel
²
,
Umar
³

2020
Phys. Rev. C
Self Cite
30
0
20
0
View full text Add to dashboard Cite

Background: Production of neutron-rich nuclei is of vital importance to both understanding nuclear structure far from stability and to informing astrophysical models of the rapid neutron capture process (r-process). Multinucleon transfer (MNT) in heavy-ion collisions offers a possibility to produce neutron-rich nuclei far from stability. Purpose: The 176 Yb + 176 Yb reaction has been suggested as a potential candidate to explore the neutron-rich region surrounding the principal fragments. The current study has been conducted with the goal of providing guidance for future experiments wishing to study this (or similar) system. Methods: Time-dependent Hartree-Fock (TDHF) and its time-dependent random-phase approximation (TDRPA) extension are used to examine both scattering and MNT characteristics in 176 Yb + 176 Yb. TDRPA calculations are performed to compute fluctuations and correlations of the neutron and proton numbers, allowing for estimates of primary fragment production probabilities. Results: Both scattering results from TDHF and transfer results from the TDRPA are presented for different energies, orientations, and impact parameters. In addition to fragment composition, scattering angles and total kinetic energies, as well as correlations between these observables are presented. Conclusions: 176 Yb + 176 Yb appears to be an interesting probe for the mid-mass neutron-rich region of the chart of nuclides. The predictions of both TDHF and TDRPA are speculative, and will benefit from future experimental results to test the validity of this approach to studying MNT in heavy, symmetric collisions.

show abstract

“…We also refer to recent applications of the SMF approach for the multinucleon transfer mechanism in the dissipation heavy-ion collisions in Refs. [23][24][25][26][27][28][29][30][31][32].…”

Section: Fluctuation Of the Relative Momenta Within The Smf Approachmentioning

confidence: 99%

“…[21,22], for recent reviews.) To provide a reliable prediction for production of yet-unknown unstable nuclei, it is of paramount importance to properly describe not only dispersions of mass and charge of reaction products, as was greatly improved by the recent developments of the SMF approach [23][24][25][26][27][28][29][30][31][32], but also the distribution of dissipated relative kinetic energy during the collision. The latter is directly connected with excitation energies of reaction products, which should not be too large to maximize the production yield.…”

Section: Introductionmentioning

confidence: 99%

Kinetic energy dissipation and fluctuations in strongly-damped heavy-ion collisions within the stochastic mean-field approach

Ayik,

Sekizawa

2020

Preprint

View full text Add to dashboard Cite

Background: Microscopic mean-field approaches have been successful in describing the most probable reaction outcomes in low-energy heavy-ion reactions. However, those approaches are known to severely underestimate dispersions of observables around the average values that has limited their applicability. Recently it has been shown that a quantal transport approach based on the stochastic mean-field (SMF) theory significantly improves the description, while its application has been limited so far to fragment mass and charge dispersions.Purpose: In this work, we extend the quantal transport approach based on the SMF theory for relative kinetic energy dissipation and angular momentum transfer in low-energy heavy-ion reactions.Methods: Based on the SMF concept, analytical expressions are derived for the radial and tangential friction and associated diffusion coefficients. Those quantal transport coefficients are calculated microscopically in terms of single-particle orbitals within the time-dependent Hartree-Fock (TDHF) approach.Results: As the first application of the proposed formalism, we consider the radial linear momentum dispersion, neglecting the coupling between radial and angular momenta. We analyze the total kinetic energy (TKE) distribution of binary reaction products in the 136 Xe+ 208 Pb reaction at Ec.m. = 526 MeV and compare with experimental data. From time evolution of single-particle orbitals in TDHF, the radial diffusion coefficient is computed on a microscopic basis, while a phenomenological treatment is introduced for the radial friction coefficient. By solving the quantal diffusion equation for the radial linear momentum, the dispersion of the radial linear momentum is obtained, from which one can construct the TKE distribution. We find that the calculations provide a good description of the TKE distribution for large values of energy losses, TKEL 150 MeV. However, the calculations underestimate the TKE distribution for smaller energy losses. Further studies are needed to improve the technical details of calculations.Conclusions: It has been shown that the quantal transport approach based on the SMF theory provides a promising basis for the microscopic description of the TKE distribution as well as the isotopic distributions in damped collisions of heavy ions at around the Coulomb barrier.

show abstract

Heavy-isotope production in Xe136+Pb208 collisions at Ec

Cited by 23 publications

References 37 publications

Quantal diffusion approach for multinucleon transfer processes in the $^{58,64}$Ni+$^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

Quantal diffusion approach for multinucleon transfer processes in the $^{58,64}$Ni+$^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

Microscopic predictions for the production of neutron-rich nuclei in the reaction Yb176 + Yb176
Godbey
¹
,
Simenel
²
,
Umar
³

2020
Phys. Rev. C
Self Cite
30
0
20
0
View full text Add to dashboard Cite

Kinetic energy dissipation and fluctuations in strongly-damped heavy-ion collisions within the stochastic mean-field approach

Contact Info

Product

Resources

About

Heavy-isotope production in Xe136+Pb208 collisions at Ec

Cited by 23 publications

References 37 publications

Quantal diffusion approach for multinucleon transfer processes in the $^{58,64}$Ni+$^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

Quantal diffusion approach for multinucleon transfer processes in the $^{58,64}$Ni+$^{208}$Pb reactions: Toward the production of unknown neutron-rich nuclei

Microscopic predictions for the production of neutron-rich nuclei in the reaction Yb176 + Yb176Godbey1, Simenel2, Umar3 2020Phys. Rev. CSelf Cite300200View full textAdd to dashboardCite

Kinetic energy dissipation and fluctuations in strongly-damped heavy-ion collisions within the stochastic mean-field approach

Contact Info

Product

Resources

About

Microscopic predictions for the production of neutron-rich nuclei in the reaction Yb176 + Yb176
Godbey
¹
,
Simenel
²
,
Umar
³

2020
Phys. Rev. C
Self Cite
30
0
20
0
View full text Add to dashboard Cite