NSR Query Results
Output year order : Descending NSR database version of April 11, 2024. Search: Author = A.S.Umar Found 100 matches. 2023AR15 Phys.Rev. C 108, 064604 (2023) M.Arik, S.Ayik, O.Yilmaz, A.S.Umar Description of the multinucleon transfer mechanism for 48Ca + 244Pu and 86Kr + 198Pt reactions in a quantal transport approach
doi: 10.1103/PhysRevC.108.064604
2023AY01 Phys.Rev. C 107, 014609 (2023) S.Ayik, M.Arik, O.Yilmaz, B.Yilmaz, A.S.Umar Multinucleon transfer mechanism in 250Cf + 232Th collisions using the quantal transport description based on the stochastic mean-field approach NUCLEAR REACTIONS 232Th(250Cf, X), E(cm)=950; calculated drift path of Cf-like fragments in the head-on collision, total kinetic energy, fragments mass and charge distribution yields for different combinations of 250Cf and 232Th orientations, primary and secondary production σ, mean values of neutron and proton numbers of Cf-like fragments, diffusion coefficients. Stochastic mean field approach which provides an extension to the standard time-dependent Hartree-Fock theory by including mean-field fluctuations.
doi: 10.1103/PhysRevC.107.014609
2023AY04 Phys.Rev. C 108, 054605 (2023) S.Ayik, M.Arik, E.Erbayri, O.Yilmaz, A.S.Umar Multinucleon transfer mechanism in 160Gd + 186W collisions in stochastic mean-field theory
doi: 10.1103/PhysRevC.108.054605
2023GU19 Phys.Rev. C 108, L051602 (2023) Role of isospin composition in low-energy nuclear fusion
doi: 10.1103/PhysRevC.108.L051602
2023UM01 Phys.Rev. C 107, 064605 (2023) Cluster model of 12C in the density functional theory framework NUCLEAR STRUCTURE 12C; calculated 3-α energy surface, total density for the ground state configuration of the 3 α particles, angular momentum projection of the 12C ground state configuration, total density for the bent-arm state configuration of the 3 α particles, localization function of the bent-arm state configuration. Framework to study the cluster structures based on density constrained Hartree-Fock approach. Showed that the 12C ground state is an equilateral triangle, which has a molecular type configuration.
doi: 10.1103/PhysRevC.107.064605
2022GO12 Phys.Rev. C 106, L051602 (2022) Theoretical uncertainty quantification for heavy-ion fusion NUCLEAR REACTIONS 48Ca(48Ca, X), E(cm)=45-61 MeV; 40Ca(40Ca, X), E(cm)=49-67 MeV; 48Ca(40Ca, X), E(cm)=46-67 MeV; 16O(208Pb, X), E(cm)=67-95 MeV; calculated fusion σ(E), theoretical model uncertainties. Quantified the uncertainties arising from uncertainties of the calculations input parameters. Density constrained time-dependent Hartree-Fock TDHF method (DC-TDHF). Comparison to experimental data.
doi: 10.1103/PhysRevC.106.L051602
2022SU07 Phys.Rev. C 105, 034601 (2022) Microscopic study of the fusion reactions 40, 48Ca+78Ni and the effect of the tensor force NUCLEAR REACTIONS 78Ni(40Ca, X), (48Ca, X), E(cm)=70, 80, 90 MeV; calculated internuclear potentials, fusion σ. Dynamic density-constrained time-dependent Hartree-Fock (DC-TDHF) and static Hartree-Fock theory. Discussed role of tensor force in the fusion of nuclei.
doi: 10.1103/PhysRevC.105.034601
2021AY06 Phys.Rev. C 104, 054614 (2021) S.Ayik, M.Arik, E.C.Karanfil, O.Yilmaz, B.Yilmaz, A.S.Umar Quantal diffusion description of isotope production via the multinucleon transfer mechanism in 48Ca + 238U collisions NUCLEAR REACTIONS 238U(48Ca, X), E(cm)=193 MeV; calculated neutron and proton diffusion coefficients, mean drift path of the projectile-like fragments, neutron, proton, and mixed variances as a functions of time and initial orbital angular momentum, orbital angular momentum, final average total kinetic energy (TKE), average total excitation energy, and scattering angles, mean values of mass and charge numbers of initial and final fragments, combined primary yield of multi-nucleon transfer and binary fission as function fragment mass, isotopic production σ for 238U(48Ca, X), E(cm)=193.1 MeV; calculated production σ for primary and secondary isotopes of A=150-200 Tb, Dy, Ho and Er, A=160-210 Tm, Yb, Lu and Hf, A=170-220 Ta, W, Re and Os, and A=180-230 Ir, Pt, Au and Hg. Methods involved quantal diffusion from stochastic mean-field approach, and transport properties from time-dependent single-particle wave functions of the time-dependent Hartree-Fock theory using statistical GEMINI++ code.
doi: 10.1103/PhysRevC.104.054614
2021UM01 Phys.Rev. C 104, 034619 (2021) Pauli energy contribution to the nucleus-nucleus interaction NUCLEAR REACTIONS 40,48Ca(40Ca, X), 48Ca(48Ca, X), E not given; 208Pb(16O, X), E not given; calculated frozen neutron and proton HF density contours, nucleus-nucleus potentials from FHF, DCFHF, and DC-TDHF methods, neutron and proton contributions to the Pauli repulsion in the frozen approximation, dynamical contributions to the Pauli repulsion, proton and neutron Pauli energy and Pauli repulsion in 40Ca+40Ca system, effect of dynamical rearrangement on Pauli energy, Pauli kinetic energy (PKE) spatial distributions. Frozen Hartree Fock (FHF), density constrained frozen Hartree-Fock (DCFHF) and in the density constrained time-dependent Hartree-Fock (DC-TDHF) microscopic methods. Relevance to impact of Pauli exclusion principle on various models and approaches of calculating the interaction of two nuclei.
doi: 10.1103/PhysRevC.104.034619
2020AY06 Phys.Rev. C 102, 024619 (2020) S.Ayik, B.Yilmaz, O.Yilmaz, A.S.Umar Merging of transport theory with the time-dependent Hartree-Fock approach: Multinucleon transfer in U + U collisions NUCLEAR REACTIONS 238U(238U, X), E(cm)=833 MeV; calculated density profile and the geometry of the collisions, values of final masses and charges of the projectile-like and target-like fragments, final orbital angular momentum, total kinetic energy (TKE), total excitation energy, center of mass angle, laboratory scattering angles for tip-tip and side-side collisions, asymptotic values of the neutron, the proton and the mixed dispersions, neutron and proton diffusion coefficients, production σ(N, Z), σ(A), σ(Z) for primary fragments, production σ(A) of gold isotopes averaged over tip-tip and side-side geometries as a function of the mass numbers, and compared with experimental data. 240Cm(236Ra, X), E(cm)=833 MeV; calculated drift path of the radium-like fragments in central collisions, neutron and proton numbers of radium-like fragments as function of time, neutron and proton diffusion coefficients. Multinucleon transfer mechanism treated in the framework of quantal diffusion description based on the stochastic mean-field (SMF) properties derived from the time-dependent Hartree-Fock (TDHF) wave functions.
doi: 10.1103/PhysRevC.102.024619
2020GO03 Phys.Rev. C 101, 034602 (2020) Microscopic predictions for the production of neutron-rich nuclei in the reaction 176Yb + 176Yb NUCLEAR REACTIONS 176Yb(176Yb, X), E(cm)=660, 880 MeV; calculated scattering angles, total kinetic energies of the outgoing fragments, particle number fluctuations and correlations, mass-angle and mass-energy distributions, primary fragments production σ(E), production σ(E) of NZ, ZZ and NN nuclei using time-dependent Hartree-Fock (TDHF) calculations and its time-dependent random-phase approximation (TDRPA) extension for scattering and multi-nucleon transfer (MNT) characteristics. Relevance to r process in nuclear astrophysical models.
doi: 10.1103/PhysRevC.101.034602
2020HU08 Phys.Rev. C 101, 061601 (2020) S.Hudan, R.T.deSouza, A.S.Umar, Z.Lin, C.J.Horowitz Enhanced dynamics in fusion of neutron-rich oxygen nuclei at above-barrier energies NUCLEAR REACTIONS 12C(16O, X), (17O, X), (18O, X), (19O, X), E(cm)=7-20 MeV; calculated above-barrier fusion σ(E) using static and dynamical microscopic model. Comparison with experimental data, and with CCFULL, TDHF and FHF calculations.
doi: 10.1103/PhysRevC.101.061601
2020SI08 Phys.Rev.Lett. 124, 212504 (2020) Timescales of Quantum Equilibration, Dissipation and Fluctuation in Nuclear Collisions NUCLEAR REACTIONS 238U(40Ca, X), 249Bk(48Ca, X), (50Ti, X), 186W(54Cr, X), E not given; analyzed available data; calculated timescales in collisions of atomic nuclei using fully microscopic approaches using time-dependent Hartree-Fock and time-dependent random-phase approximation.
doi: 10.1103/PhysRevLett.124.212504
2020ZH02 Phys.Lett. B 801, 135170 (2020), Corrigendum Phys.Lett. B 803, 135278 (2020) N.T.Zhang, X.Y.Wang, D.Tudor, B.Bucher, I.Burducea, H.Chen, Z.J.Chen, D.Chesneanu, A.I.Chilug, L.R.Gasques, D.G.Ghita, C.Gomoiu, K.Hagino, S.Kubono, Y.J.Li, C.J.Lin, W.P.Lin, R.Margineanu, A.Pantelica, I.C.Stefanescu, M.Straticiuc, X.D.Tang, L.Trache, A.S.Umar, W.Y.Xin, S.W.Xu, Y.Xu Constraining the 12C+12C astrophysical S-factors with the 12C+13C measurements at very low energies NUCLEAR REACTIONS 12C(13C, p)24Na, E=4.640-10.995 MeV; measured reaction products, Eγ, Iγ; deduced σ, branching ratio, S-factor.
doi: 10.1016/j.physletb.2019.135170
2019AY02 Phys.Rev. C 100, 014609 (2019) S.Ayik, B.Yilmaz, O.Yilmaz, A.S.Umar Quantal diffusion approach for multinucleon transfers in Xe + Pb collisions NUCLEAR REACTIONS 136Xe(208Pb, X), 130Te(214Po, X), 138Ce(206Pt, X), E(cm)=526 MeV; calculated distribution of projectile-like and target-like reaction product by mass number and charge for 208Pb+136Xe reaction, neutron and proton diffusion coefficients and drift paths using quantal diffusion approach.
doi: 10.1103/PhysRevC.100.014609
2019AY06 Phys.Rev. C 100, 044614 (2019) S.Ayik, O.Yilmaz, B.Yilmaz, A.S.Umar Heavy-isotope production in 136Xe 208Pb collisions at Ec.m. = 514 MeV NUCLEAR REACTIONS 208Pb(136Xe, X)210Po/222Rn/224Ra, E(cm)=514 MeV; calculated TKE, excitation energy, scattering angles, mass dispersions toward asymmetry and symmetry directions, production σ for A=110-230 isotopes, and for primary isotopes of Z=84, 86 and 88 as a function of mass number using stochastic mean field (SMF) approach. Comparison with experimental data.
doi: 10.1103/PhysRevC.100.044614
2019GO17 Phys.Rev. C 100, 024610 (2019) Deformed shell effects in 48Ca + 249Bk quasifission fragments NUCLEAR REACTIONS 249Bk(48Ca, X), E(cm)=234 MeV; calculated total kinetic energies of quasifission fragments as a function of their mass ratio and compared to Viola systematics, mass-angle correlations, yields of fragments by mass, proton and neutron numbers, distribution of scattering angle as function of mass ratio, proton and neutron numbers using time-dependent Hartree-Fock simulations. Influence of shell effects, and orientation of the deformed target in the entrance channel in the formation of the fragments. Relevance to optimization of entrance channels for the formation of superheavy nuclei (SHN).
doi: 10.1103/PhysRevC.100.024610
2019GO18 Phys.Rev. C 100, 024619 (2019) Absence of hindrance in a microscopic 12C + 12C fusion study NUCLEAR REACTIONS 12C(12C, X), E(cm)=2-12 MeV; calculated fusion σ(E) and astrophysical S(E) factors using a static Hartree-Fock and time-dependent Hartree-Fock mean-field method; no S factor maximum observed, and no extreme sub-barrier hindrance predicted at low energies. Comparison with experimental data.
doi: 10.1103/PhysRevC.100.024619
2019GO28 Phys.Rev. C 100, 054612 (2019) Influence of the tensor interaction on heavy-ion fusion cross sections NUCLEAR REACTIONS 12C(12C, X), (13C, X), E(cm)=1-7 MeV; 40Ca(40Ca, X), (48Ca, X), 48Ca(48Ca, X), E(cm)=46-59 MeV; 48Ca(48Ca, X), E(cm)=45-63 MeV; 48Ca(110Sn, X), (116Sn, X), (120Sn, X), E(cm)=106-130 MeV; 208Pb(16O, X), E(cm)=69-84 MeV; calculated fusion σ(E), and S factors for 12C reactions using the fully microscopic density constrained time-dependent Hartree-Fock (DC-TDHF) method with the Skyrme SLy5 and SLy5t tensor interactions; deduced that inclusion of tensor interaction has measurable effect on the fusion cross sections.
doi: 10.1103/PhysRevC.100.054612
2018AY03 Phys.Rev. C 97, 054618 (2018) S.Ayik, B.Yilmaz, O.Yilmaz, A.S.Umar Quantal diffusion description of multinucleon transfers in heavy-ion collisions NUCLEAR REACTIONS 238U(48Ca, X), E(cm)=193 MeV; calculated collision density profile, neutron and proton mean-drift path, drift and diffusion coefficients, curvature parameters, covariance of fragment mass distribution, impact parameter, final orbital angular momentum, final average total kinetic energy TKE, average total excitation energy, scattering angles, mass and charge numbers of final fragments, yield and production cross section of primary fragments. Stochastic mean-field (SMF) approach with a quantal diffusion description of the multi-nucleon transfer in heavy-ion collisions at finite impact parameters. Comparison with experimental data.
doi: 10.1103/PhysRevC.97.054618
2018GU20 Phys.Rev. C 98, 064607 (2018) Influence of the tensor force on the microscopic heavy-ion interaction potential NUCLEAR REACTIONS 12C(12C, X), E(cm)=8 MeV; 16O(16O, X), E(cm)=12 MeV; 40Ca(40Ca, X), E(cm)=55 MeV; 40,48Ca(48Ca, X), E(cm)=55 MeV; 56Ni(56Ni, X), E(cm)=105 MeV; 56Ni(48Ca, X), E(cm)=75; 100,116,120Sn(48Ca, X), E(cm)=125 MeV; calculated internuclear potentials with and without Skyrme tensor force using static Hartree-Fock and dynamic density-constrained time-dependent Hartree-Fock (DC-TDHF) theory. Discussed role of tensor force in the fusion of nuclei.
doi: 10.1103/PhysRevC.98.064607
2018SI24 Prog.Part.Nucl.Phys. 103, 19 (2018) Heavy-ion collisions and fission dynamics with the time-dependent Hartree-Fock theory and its extensions
doi: 10.1016/j.ppnp.2018.07.002
2018UM01 Acta Phys.Pol. B49, 573 (2018) TDHF Investigations of the U+U Quasifission Process NUCLEAR REACTIONS 238U(238U, x), E(cm)=850-1350 MeV; calculated possibilities of reaching high-Z rich isotopes using unrestricted TDHF, Skyrme Hartree-Fock, Quantum Molecular Dynamics (QMD), Improved QMD (ImQMD), Dinuclear Nuclear System (DNS), Relativistic Mean-Field (RMF), Time-Dependent Hartree-Fock (TDHF), Density Constrained TDHF (DC-TDHF)(evaporation residue σ strongly reduced due to Quasifission (QF) and Fusion-Fission (FF)); calculated evolution of central collisions, reaching (in tip-side oriented collision) exit heavy fragment of Z≈ 194 and A≈325, nuclear contact time for E(cm)=850-1350 MeV for tip-side and tip-tip orientations, also with ternary fission possibility and shown with the ternary fragment of Z≈7 shown in the calculations; calculated final E* vs E at central collisions.
doi: 10.5506/aphyspolb.49.573
2018UM02 Nuovo Cim. C 41, 173 (2018) Equilibration dynamics and isospin effects in nuclear reactions NUCLEAR REACTIONS 249Bk(48Ca, X), E(cm)=234 MeV; 186W(54Cr, X), E(cm)=218.6 MeV; 208Pb(78Kr, X), E=8.5 MeV/nucleon; analyzed available data; calculated equilibration times for mass, isospin, and TKE (total kinetic energy). TDFHF approach.
doi: 10.1393/ncc/i2018-18173-9
2018YI04 Phys.Rev. C 98, 034604 (2018) B.Yilmaz, S.Ayik, O.Yilmaz, A.S.Umar Multinucleon transfer in 58Ni + 60Ni and 60Ni + 60Ni in a stochastic mean-field approach NUCLEAR REACTIONS 60Ni(58Ni, X), (60Ni, X), E(cm)=135.6 MeV; calculated density profiles, neutron and proton diffusion coefficients, one-sided mean drift paths, collision covariances, dispersion per unit mass, and fragment mass distribution using stochastic mean-field (SMF) approach. Comparison with experimental values and time-dependent random-phase approximation (TDRPA) calculations.
doi: 10.1103/PhysRevC.98.034604
2017AY05 Phys.Rev. C 96, 024611 (2017) S.Ayik, B.Yilmaz, O.Yilmaz, A.S.Umar, G.Turan Multinucleon transfer in central collisions of 238U + 238U NUCLEAR REACTIONS 238U(238U, X), E(cm)=900, 1050 MeV; calculated density profiles in the reaction plane, and mean drift path of the projectile-like fragments using time-dependent Hartree-Fock (TDHF) approach, quantal neutron and proton diffusion coefficients, memory effects and covariances, primary fragment mass distributions using stochastic mean-field (SMF) approach.
doi: 10.1103/PhysRevC.96.024611
2017GO03 Phys.Rev. C 95, 011601 (2017) Dependence of fusion on isospin dynamics NUCLEAR REACTIONS 48Ca(40Ca, X), E(cm)=55 MeV; 208Pb(16O, X), E(cm)=75, 90, 120 MeV; 208Pb(48Ca, X), (50Ti, X), E(cm)/VB=1.065; 40,48Ca(132Sn, X), E(cm)=75 MeV; calculated total and isoscalar density-constrained time-dependent Hartree-Fock (DC-TDHF) potentials. 40Ca(132Sn, X), E(cm)=108-140 MeV; calculated fusion σ(E). Time-dependent Hartree-Fock theory and isoscalar and isovector properties of energy density functional (EDF).
doi: 10.1103/PhysRevC.95.011601
2017SI03 Phys.Lett. B 765, 99 (2017) V.Singh, J.Vadas, T.K.Steinbach, B.B.Wiggins, S.Hudan, R.T.deSouza, Z.Lin, C.J.Horowitz, L.T.Baby, S.A.Kuvin, V.Tripathi, I.Wiedenhover, A.S.Umar Fusion enhancement at near and sub-barrier energies in 19O + 12C NUCLEAR REACTIONS 12C(18O, X), (19O, X), E(cm)<20 MeV; measured reaction products; deduced σ. comparison with a state-of-the-art microscopic model.
doi: 10.1016/j.physletb.2016.12.017
2017SI06 Phys.Rev. C 95, 031601 (2017) C.Simenel, A.S.Umar, K.Godbey, M.Dasgupta, D.J.Hinde How the Pauli exclusion principle affects fusion of atomic nuclei NUCLEAR REACTIONS 40Ca(40Ca, X), E(cm)=48-64 MeV; 48Ca(48Ca, X), E(cm)=45-61 MeV; 208Pb(16O, X), E(cm)=65-90 MeV; calculated nucleus-nucleus potentials with and without Pauli exclusion principle, fusion σ(E), FHF and DCFHF σ(E) without couplings. 16O(16O, X), 40Ca(40Ca, X), 48Ca(40Ca, X), 208Pb(48Ca, X); calculated nucleus-nucleus potentials without (FHF) and with (DCFHF) Pauli exclusion principle. Coupled-channel calculations using CCFULL code, and Woods-Saxon fits of the Frozen Hartree-Fock (FHF) and density-constrained frozen Hartree-Fock (DCFHF) potentials. Comparison with experimental data.
doi: 10.1103/PhysRevC.95.031601
2017UM01 Phys.Rev. C 96, 024625 (2017) Transport properties of isospin asymmetric nuclear matter using the time-dependent Hartree-Fock method NUCLEAR REACTIONS 208Pb(78Kr, X), (92Kr, X), E=8.5 MeV/nucleon; calculated impact parameter and energy-loss dependence of relevant observables, neutron and proton numbers transferred to and from the projectile-like fragments (PLFs), neutron and proton numbers of the PLFs as a function of impact parameter and the angle representing initial orientation of deformed projectile with respect to the beam axis, deflection functions, final kinetic energy versus the scattering angle for the reactions, sticking time as a function of impact parameter, N/Z values for PLFs and target-like fragments (TLFs) as a function of energy loss, (N-Z)/A values of primary PLFs and TLFs as function of contact time between the collision partners, distribution of PLF neutron and proton numbers in the N-Z plane, percent of total excitation energy carried by the PLFs as a function of energy loss. Time-dependent density-constrained Hartree-Fock (TDHF) method in full three dimensions.
doi: 10.1103/PhysRevC.96.024625
2016AY06 Phys.Rev. C 94, 044624 (2016) S.Ayik, O.Yilmaz, B.Yilmaz, A.S.Umar Quantal nucleon diffusion: Central collisions of symmetric nuclei NUCLEAR REACTIONS 28O(28O, X), E(cm)=8.7 MeV; 40Ca(40Ca, X), E(cm)=52.7 MeV; 48Ca(48Ca, X), E(cm)=50.7 MeV; 56Ni(56Ni, X), E(cm)=100.0 MeV; calculated quantal and semiclassical neutron and proton diffusion coefficients, effect of Pauli blocking on fragment neutron and proton variances using stochastic mean-field (SMF) approach.
doi: 10.1103/PhysRevC.94.044624
2016RE07 Phys.Rev. C 93, 044618 (2016) P.-G.Reinhard, A.S.Umar, P.D.Stevenson, J.Piekarewicz, V.E.Oberacker, J.A.Maruhn Sensitivity of the fusion cross section to the density dependence of the symmetry energy NUCLEAR REACTIONS 48Ca(48Ca, X)96Zr*, E(cm)=45-65 MeV; calculated folding model ion-ion interaction potentials, fusion σ(E). Impact of nuclear fusion on the nuclear equation of state (EOS). 48Ca; calculated Neutron root-mean-square radius (rms), neutron diffraction radius, and neutron halo. Dynamic microscopic method based on density-constrained time-dependent Hartree-Fock (DC-TDHF) approach, and direct TDHF study of barrier cross sections using a family of Skyrme parametrization.
doi: 10.1103/PhysRevC.93.044618
2016ST13 Phys.Rev. C 93, 054617 (2016) P.D.Stevenson, E.B.Suckling, S.Fracasso, M.C.Barton, A.S.Umar Skyrme tensor force in heavy ion collisions NUCLEAR REACTIONS 16O(16O, X), E(cm)=100 MeV; calculated contributions from terms involving time-odd densities and currents to the total energy as the sum of isoscalar and isovector contributions, energy contributions from (pseudo)scalar-, vector- and (pseudo)tensor-decomposed form of spin-current tensor J. Symmetry-unrestricted Time-dependent Hartree-Fock (TDHF) energy density functional calculations with full version of Skyrme force, including terms arising only from the Skyrme tensor force. Discussed role of Skyrme tensor force in dynamic processes in nuclei.
doi: 10.1103/PhysRevC.93.054617
2016TO05 Phys.Rev. C 93, 034607 (2016) Two-body dissipation effects on the synthesis of superheavy elements NUCLEAR REACTIONS 208Pb(82Ge, X), E(cm)=284, 292-388, 468-626 MeV; 208Pb(84Se, X), E(cm)=299, 298-403 MeV; 208Pb(86Kr, X), E(cm)=341 MeV; 208Pb(88Sr, X), E(cm)=340 MeV; calculated contour density plots for low-energy head-on collisions. Synthesis of superheavy elements. Time-dependent density-matrix theory (TDDM), as an extension of the time-dependent Hartree-Fock (TDHF) theory.
doi: 10.1103/PhysRevC.93.034607
2016UM04 Phys.Rev. C 94, 024605 (2016) A.S.Umar, V.E.Oberacker, C.Simenel Fusion and quasifission dynamics in the reactions 48Ca + 249Bk and 50Ti + 249Bk using a time-dependent Hartree-Fock approach NUCLEAR REACTIONS 249Bk(48Ca, X), E(cm)=211, 218, 193-230 MeV; 249Bk(50Ti, X), E(cm)=233.2, 205-245 MeV; calculated contact time, mass and charge of the light fragment, and excitation energies of the heavy and light fragments as function of incident energy, mass-angle and mass-TKE distributions. Unrestricted time-dependent Hartree-Fock (TDHF) calculations, and the density-constrained TDHF method to extract NN potentials and excitation energy in each fragment. Relevance to the production of Z=117 and 119 superheavy elements, and fusion and quasifission processes.
doi: 10.1103/PhysRevC.94.024605
2015AY03 Phys.Rev. C 91, 054601 (2015) S.Ayik, O.Yilmaz, B.Yilmaz, A.S.Umar, A.Gokalp, G.Turan, D.Lacroix Quantal description of nucleon exchange in a stochastic mean-field approach NUCLEAR REACTIONS 40Ca(40Ca, X), E(cm)=52.7 MeV; 48Ca(48Ca, X), E(cm)=50.7 MeV; 56Ni(56Ni, X), E(cm)=99.9 MeV; calculated quantal diffusion coefficient and variance of fragment mass distribution as a function of time in central collision. Stochastic mean-field approach. Comparison with other theoretical calculations.
doi: 10.1103/PhysRevC.91.054601
2015HA12 Phys.Rev. C 91, 041602 (2015) K.Hammerton, Z.Kohley, D.J.Hinde, M.Dasgupta, A.Wakhle, E.Williams, V.E.Oberacker, A.S.Umar, I.P.Carter, K.J.Cook, J.Greene, D.Y.Jeung, D.H.Luong, S.D.McNeil, C.S.Palshetkar, D.C.Rafferty, C.Simenel, K.Stiefel Reduced quasifission competition in fusion reactions forming neutron-rich heavy elements NUCLEAR REACTIONS 180W(50Cr, X), E(cm)=222.6 MeV; 180W(52Cr, X), E(cm)=221.2 MeV; 180W(54Cr, X), E(cm)=219.8 MeV; 186W(50Cr, X), E(cm)=221.0 MeV; 184W(52Cr, X), E(cm)=220.1 MeV; 182W(54Cr, X), E(cm)=221.0 MeV; 184W(54Cr, X), E(cm)=218.9 MeV; 186W(54Cr, X), E(cm)=218.3 MeV; measured spectra of neutron-rich fragments from fusion-fission and quasifission in coincidence mode, mass-angle distributions (MADs) using the ANU CUBE detector system at ANU's Heavy-Ion Accelerator Facility; deduced strong dependence on the N/Z of the compound system in quasifission system. Comparison with microscopic time-dependent Hartree-Fock calculations of the quasifission process.
doi: 10.1103/PhysRevC.91.041602
2015UM02 Phys.Rev. C 92, 024621 (2015) A.S.Umar, V.E.Oberacker, C.Simenel Shape evolution and collective dynamics of quasifission in the time-dependent Hartree-Fock approach NUCLEAR REACTIONS 238U(40Ca, X), E(cm)=211 MeV; 249Bk(48Ca, X), E(cm)=218 MeV; 238U(48Ca, X), E(cm)=203 MeV; calculated effect of moment of inertia on the angular distribution of the fragments, contour plot of the time evolution of the mass density for 249Bk+48Ca reaction, time dependence on the moments inertia, impact parameter and temperature using fully microscopic time-dependent Hartee-Fock (TDHF) approach.
doi: 10.1103/PhysRevC.92.024621
2015UM03 Phys.Rev. C 92, 025808 (2015) A.S.Umar, V.E.Oberacker, C.J.Horowitz, P.-G.Reinhard, J.A.Maruhn Swelling of nuclei embedded in neutron-gas and consequences for fusion NUCLEAR REACTIONS 28O(28O, X), E(cm)=2-14 MeV; 60Ca(60Ca, X), E(cm)=34-58 MeV; calculated pycnonuclear fusion cross sections and Astrophysical S factor as a function of external neutron-gas density, up to 500 neutrons for 28O and 1040 for 60Ca using Sao Paulo potential and incoming wave boundary condition (IWBC) method. Relevance to study of fusion of neutron rich nuclei at radioactive ion beam facilities, and to the study of composition and heating of the crust of accreting neutron stars.
doi: 10.1103/PhysRevC.92.025808
2015UM04 Nucl.Phys. A944, 238 (2015) Time-dependent HF approach to SHE dynamics NUCLEAR REACTIONS 238U(48Ca, x), E(cm)=185-250 MeV; calculated potential barrier for different mutual orientation of colliding nuclei, capture σ, deformation time dependence, inertia moment time dependence, light fragment charge and mass. 186W(54Cr, x), E=218.6 MeV;238U(40Ca, x), E(cm)=208-220 MeV; calculated quasifission time development for different mutual orientation of colliding nuclei, deformation, TKE, orientation angle between the nuclei, mass and charge differences, moment of inertia. DC-TDHF (Density Constrained TDHF). Compared with available data.
doi: 10.1016/j.nuclphysa.2015.02.011
2014OB06 Phys.Rev. C 90, 054605 (2014) V.E.Oberacker, A.S.Umar, C.Simenel Dissipative dynamics in quasifission NUCLEAR REACTIONS 238U(40Ca, X), (48Ca, X), E(cm)=209 MeV; calculated contact time, mass and charge of light fragment as function of impact parameter, total kinetic energy (TKE) of the quasifission (QF) fragments. Evidence of less QF in 48Ca+238U system than in 40Ca+238U, relevance to formation of superheavy elements (SHE). Discussed the effect due to magicity of 48Ca. TDHF calculations with Skyrme SLy4d energy density functional (EDF).
doi: 10.1103/PhysRevC.90.054605
2014SI06 Phys.Rev. C 89, 031601 (2014) Formation and dynamics of fission fragments RADIOACTIVITY 258,264Fm(SF); calculated adiabatic fission potential for symmetric fission as function of distance between fragments, time evolution of various energies using realistic mean-field computer codes, and time-dependent Hartree-Fock (TDHF) method.
doi: 10.1103/PhysRevC.89.031601
2014ST22 Phys.Rev. C 90, 041603 (2014) T.K.Steinbach, J.Vadas, J.Schmidt, C.Haycraft, S.Hudan, R.T.deSouza, L.T.Baby, S.A.Kuvin, I.Wiedenhover, A.S.Umar, V.E.Oberacker Sub-barrier enhancement of fusion as compared to a microscopic method in 18O + 12C NUCLEAR REACTIONS 12C(18O, X), E=16.25, 36 MeV; measured fragment spectra, fusion σ(E) in sub-barrier domain, time-of-flight (TOF) technique at FSU tandem accelerator facility. Pulsed beam. Comparison with previous experimental results, and with density-constrained time-dependent Hartree-Fock (DC-TDHF) and coupled channel calculations.
doi: 10.1103/PhysRevC.90.041603
2014UM01 Phys.Rev. C 89, 034611 (2014) A.S.Umar, C.Simenel, V.E.Oberacker Energy dependence of potential barriers and its effect on fusion cross sections NUCLEAR REACTIONS 40Ca(40Ca, X), E(cm)=50, 53, 60, 65 MeV; 208Pb(16O, X), E(cm)=75, 80, 100 MeV; calculated ion-ion interaction potentials, fusion σ(E), fusion barrier distributions as function of incident energy. Density-constrained and direct time-dependent Hartree-Fock (DC-TDHF) methods. Comparison with experimental data.
doi: 10.1103/PhysRevC.89.034611
2013DE23 Phys.Rev. C 88, 014602 (2013) R.T.deSouza, S.Hudan, V.E.Oberacker, A.S.Umar Confronting measured near- and sub-barrier fusion cross sections for 20O+12C with a microscopic method NUCLEAR REACTIONS 12C(20O, X), E(cm)=6-16 MeV; calculated total fusion cross section, heavy-ion potentials, averaged fusion σ. Density-constrained time-dependent Hartree-Fock (DC-TDHF) microscopic method. Comparison with σ measurements for an experiment at SPIRAL-1, GANIL facility at E(20O)=1-2 MeV/nucleon. Comparison with other theoretical calculations.
doi: 10.1103/PhysRevC.88.014602
2013OB01 Phys.Rev. C 87, 034611 (2013) Microscopic analysis of sub-barrier fusion enhancement in 132Sn+40Ca versus 132Sn+48Ca NUCLEAR REACTIONS 132Sn(40Ca, X), (48Ca, X), E(cm)=106-140 MeV; calculated heavy-ion potential, total fusion σ(E). Microscopic calculations based on density-constrained time-dependent Hartree-Fock theory (DC-TDHF) using Skyrme SLy4 interaction. Comparison with experimental data.
doi: 10.1103/PhysRevC.87.034611
2013SI21 Phys.Rev. C 88, 024617 (2013) C.Simenel, R.Keser, A.S.Umar, V.E.Oberacker Microscopic study of 16O+16O fusion NUCLEAR REACTIONS 16O(16O, X), E(cm)=6-40 MeV; calculated fusion σ(E) using three dimensional time-dependent Hartree-Fock (TDHF), and density-constrained time-dependent Hartree Fock (DC-TDHF) calculations. 16O(16O, X), E(cm)=6-13 MeV; calculated fusion σ(E) with no coupling and couplings to first 3- states in one or both nuclei using coupled-channel approach (CCFULL computer code). Discussed role of coupling to low-lying octupole states. Comparison with experimental data.
doi: 10.1103/PhysRevC.88.024617
2012KE03 Phys.Rev. C 85, 044606 (2012) R.Keser, A.S.Umar, V.E.Oberacker Microscopic study of Ca + Ca fusion NUCLEAR REACTIONS 40Ca(40Ca, X), 48Ca(40Ca, X), (48Ca, X), E(cm)=45-65; calculated total fusion σ(E), potential barriers, neutron and proton transfer, and excitation energy as a function of the ion-ion distance, isoscalar deformation parameter, power spectrum of isovector dipole amplitude. Microscopic time-dependent Hartree-Fock theory with density constraint (DC-TDHF). Comparison with experimental data.
doi: 10.1103/PhysRevC.85.044606
2012LO10 Phys.Rev. C 86, 024608 (2012) N.Loebl, A.S.Umar, J.A.Maruhn, P.-G.Reinhard, P.D.Stevenson, V.E.Oberacker Single-particle dissipation in a time-dependent Hartree-Fock approach studied from a phase-space perspective NUCLEAR REACTIONS 40Ca(40Ca, X), E(cm)=160, 200, 240 MeV; calculated β and γ deformation parameter, quadrupole moment, and volume phase-space global observables in momentum and coordinate space using the time-dependent Hartree-Fock (TDHF) theory and the Wigner distribution function in the full six-dimensional phase space. Significance of extra time-odd terms.
doi: 10.1103/PhysRevC.86.024608
2012OB02 Phys.Rev. C 85, 034609 (2012) V.E.Oberacker, A.S.Umar, J.A.Maruhn, P.-G.Reinhard Dynamic microscopic study of pre-equilibrium giant resonance excitation and fusion in the reactions 132Sn + 48Ca and 124Sn + 40Ca NUCLEAR REACTIONS 132Sn(48Ca, X), 124Sn(40Ca, X), E(cm)=130 MeV; calculated time evolution of isoscalar quadrupole moment, deformation parameter and rms charge radius, isovector quadrupole moment, dipole amplitude, neutron leakage, pre-equilibrium dipole radiation spectrum, total fusion cross sections, heavy-ion potential, microscopic mass parameter. Pre-equilibrium Giant dipole resonance (GDR) excitation. Density-constrained time-dependent Hartree-Fock (TDHF) method. Comparison with experimental data.
doi: 10.1103/PhysRevC.85.034609
2012UM01 Phys.Rev. C 85, 017602 (2012) A.S.Umar, V.E.Oberacker, J.A.Maruhn, P.-G.Reinhard Microscopic composition of ion-ion interaction potentials NUCLEAR REACTIONS 16O(16O, X), (24O, X), E(cm)=12 MeV; 40Ca(40Ca, X), E(cm)=55 MeV; 132Sn(48Ca, X), E(cm)=120 MeV; calculated ion-ion interaction potentials for head-on collisions using TDHF approach for the time evolution of the nuclear collision.
doi: 10.1103/PhysRevC.85.017602
2012UM02 Phys.Rev. C 85, 055801 (2012) A.S.Umar, V.E.Oberacker, C.J.Horowitz Microscopic sub-barrier fusion calculations for the neutron star crust NUCLEAR REACTIONS 12C, 16,24,28O(16O, X), (24O, X), E(cm)=2-13 MeV; calculated nuclear density contours, potential barriers, fusion σ(E), astrophysical S factor. Time-dependent Hartree-Fock theory with density-constrained Hartree-Fock calculations. Comparison with Sao Paulo static barrier penetration model and experimental data.
doi: 10.1103/PhysRevC.85.055801
2011RE05 Phys.Rev. C 83, 034312 (2011) P.-G.Reinhard, J.A.Maruhn, A.S.Umar, V.E.Oberacker Localization in light nuclei NUCLEAR STRUCTURE 4He, 8Be, 12,20C, 16O, 20Ne, 24Mg, 28Si; calculated contours of proton localization and total density. Spatial localization of light nuclei within the Hartree-Fock approximation.
doi: 10.1103/PhysRevC.83.034312
2010OB01 Phys.Rev. C 82, 034603 (2010) V.E.Oberacker, A.S.Umar, J.A.Maruhn, P.-G.Reinhard Microscopic study of the 132, 124Sn+96Zr reactions: Dynamic excitation energy, energy-dependent heavy-ion potential, and capture cross section NUCLEAR REACTIONS 96Zr(124Sn, X), (132Sn, X), (134Sn, X), E(cm)=195-260 MeV; calculated mass density contour plots, potential barriers, intrinsic mass quadrupole moment, heavy ion potential barriers, precompound excitation energy, capture and inelastic cross sections using time-dependent Hartree-Fock (TDHF) and density-constrained time-dependent Hartree-Fock methods (DC-TDHF).
doi: 10.1103/PhysRevC.82.034603
2010UM01 Phys.Rev.Lett. 104, 212503 (2010) A.S.Umar, J.A.Maruhn, N.Itagaki, V.E.Oberacker Microscopic Study of the Triple-α Reaction NUCLEAR REACTIONS 8Be(α, X)12C, E(cm)=2 MeV; calculated time evolution, potential energy curves for 4He + 8Be head-n collision, single-particle parities of the neutron states; deduced formation of a metastable linear chain state of three α-like clusters. Time-dependent Hartree-Fock theory.
doi: 10.1103/PhysRevLett.104.212503
2010UM02 Phys.Rev. C 81, 064607 (2010) A.S.Umar, V.E.Oberacker, J.A.Maruhn, P.-G.Reinhard Entrance channel dynamics of hot and cold fusion reactions leading to superheavy elements NUCLEAR REACTIONS 208Pb(70Zn, X), E(cm)=260-350 MeV; 238U(48Ca, X), E(cm)=180-250 MeV; calculated potential barriers, excitation energies, and capture σ using fully microscopic time-dependent Hartree-Fock theory coupled with a density constraint. Comparison with experimental data.
doi: 10.1103/PhysRevC.81.064607
2009UM01 J.Phys.(London) G36, 025101 (2009) Center-of-mass motion and cross-channel coupling in the time-dependent Hartree-Fock theory
doi: 10.1088/0954-3899/36/2/025101
2009UM03 Eur.Phys.J. A 39, 243 (2009) Density-constrained time-dependent Hartree-Fock calculation of 16O + 208Pb fusion cross-sections NUCLEAR REACTIONS 208Pb(16O, X), E(cm)=65-110 MeV; calculated total fusion σ using energy-dependent density-constrained time-dependent Hartree-Fock method. Comparison with data.
doi: 10.1140/epja/i2008-10712-5
2009UM04 Phys.Rev. C 80, 041601 (2009) A.S.Umar, V.E.Oberacker, J.A.Maruhn, P.-G.Reinhard Microscopic calculation of pre-compound excitation energies for heavy-ion collisions NUCLEAR REACTIONS 16O(16O, X), E(cm)=11, 20, 34, 50 MeV; 34Ne(16O, X), E(cm)=11, 15, 30 MeV; 40Ca(40Ca, X), E(cm)=55, 60, 80, 100 MeV;calculated excitation energies, internuclear potentials, and ion-ion potentials for head-on collisions using time-dependent Hartree-Fock (TDHF) theory.
doi: 10.1103/PhysRevC.80.041601
2008UM03 Phys.Rev. C 77, 064605 (2008) 64Ni+64Ni fusion reaction calculated with the density-constrained time-dependent Hartree-Fock formalism NUCLEAR REACTIONS 64Ni(64Ni, X), E(cm)=86-110 MeV; calculated orientation probabilities, potential barriers, density contours, σ. Time-dependent Hartree-Fock model.
doi: 10.1103/PhysRevC.77.064605
2008UM04 Eur.Phys.J. A 37, 245 (2008) A.S.Umar, V.E.Oberacker, J.A.Maruhn Neutron transfer dynamics and doorway to fusion in time-dependent Hartree-Fock theory NUCLEAR REACTIONS 24O(16O, X), E(cm)=7, 8, 9 MeV; 96Zr(40Ca, X), E(cm)=91, 97 MeV; calculated neutron and single-particle probability densities, potential barrier using time-dependent Hartree-Fock model.
doi: 10.1140/epja/i2008-10614-6
2007UM02 Phys.Rev. C 76, 014614 (2007) 64Ni+132Sn fusion within the density-constrained time-dependent Hartree-Fock formalism NUCLEAR REACTIONS 132Sn(64Ni, f)E(cm)<200 MeV; calculated fusion cross sections using the density constrained time-dependent Hartree-Fock formalism.
doi: 10.1103/PhysRevC.76.014614
2007UM03 Phys.Rev. C 76, 024316 (2007) Compressibility and equation of state of finite nuclei
doi: 10.1103/PhysRevC.76.024316
2006UM02 Phys.Rev. C 73, 054607 (2006) Three-dimensional unrestricted time-dependent Hartree-Fock fusion calculations using the full Skyrme interaction NUCLEAR REACTIONS 16O(16O, X), E(cm)=34 MeV; calculated fusion σ. Three-dimensional unrestricted time-dependent Hartree-Fock approach, Skyrme interaction.
doi: 10.1103/PhysRevC.73.054607
2006UM03 Phys.Rev. C 74, 021601 (2006) Heavy-ion interaction potential deduced from density-constrained time-dependent Hartree-Fock calculation NUCLEAR REACTIONS 16O(16O, X), E(cm)=34 MeV; 22Ne(16O, X), E(cm)=50 MeV; calculated internuclear potentials. Density-constrained time-dependent Hartree-Fock calculation.
doi: 10.1103/PhysRevC.74.021601
2006UM04 Phys.Rev. C 74, 024606 (2006) Time dependent Hartree-Fock fusion calculations for spherical, deformed systems NUCLEAR REACTIONS 162Dy(64Ni, 64Ni'), E(cm)=200, 265 MeV; calculated Coulomb excitation probabilities for ground-state rotational band, dynamic alignment features. 22Ne(16O, X), E(cm)=95 MeV; calculated dynamic alignment due to Coulomb excitation, fusion σ vs orientation. Time dependent Hartree-Fock approach.
doi: 10.1103/PhysRevC.74.024606
2006UM06 Phys.Rev.C 74, 061601 (2006) Dynamical deformation effects in subbarrier fusion of 64Ni+132Sn NUCLEAR REACTIONS 132Sn(64Ni, X), E(cm)=140-180 MeV; calculated internuclear potential, fusion σ, dynamical deformation effects.
doi: 10.1103/PhysRevC.74.061601
2005BL12 Phys.Rev. C 71, 054321 (2005) A.Blazkiewicz, V.E.Oberacker, A.S.Umar, M.Stoitsov Coordinate space Hartree-Fock-Bogoliubov calculations for the zirconium isotope chain up to the two-neutron drip line NUCLEAR STRUCTURE 102,104,106,108,110,112,114,116,118,120,122,124Zr; calculated binding energies, two-neutron separation energies, quadrupole moments, β2, radii, pairing energies. Hartree-Fock-Bogoliubov approach.
doi: 10.1103/PhysRevC.71.054321
2005BL32 Eur.Phys.J. A 25, Supplement 1, 543 (2005) A.Blazkiewicz, V.E.Oberacker, A.S.Umar 2-D lattice HFB calculations for neutron-rich zirconium isotopes NUCLEAR STRUCTURE 102,104,106,108,110,112,114,116,118,120,122Zr; calculated two-neutron separation energies, quadrupole moments, radii. Hartree-Fock-Bogoliubov approach.
doi: 10.1140/epjad/i2005-06-100-7
2005UM01 Phys.Rev. C 71, 034314 (2005) Time-dependent response calculations of nuclear resonances NUCLEAR STRUCTURE 16O, 32S, 40Ca; calculated giant resonance response functions, time-dependent features.
doi: 10.1103/PhysRevC.71.034314
2005UM02 Eur.Phys.J. A 25, Supplement 1, 553 (2005) TDHF studies with modern Skyrme forces NUCLEAR REACTIONS 22Ne(16O, X), E=2.5 MeV/nucleon; calculate density distributions vs time; deduced orientation effects on fusion σ. Three-dimensional time-dependent Hartree-Fock approach, Skyrme forces.
doi: 10.1140/epjad/i2005-06-087-y
2003OB06 Phys.Rev. C 68, 064302 (2003) V.E.Oberacker, A.S.Umar, E.Teran, A.Blazkiewicz Hartree-Fock-Bogoliubov calculations in coordinate space: Neutron-rich sulfur, zirconium, cerium, and samarium isotopes NUCLEAR STRUCTURE 32,34,36,38,40,42,44,46,48,50,52S; calculated two-neutron separation energies, quadrupole moments, radii. 102,104Zr, 152Ce, 156Nd, 160Sm; calculated deformation parameters, radii. 158Sm; calculated ground-state binding energy, pairing energies, radii, density distributions. Hartree-Fock-Bogoliubov approach.
doi: 10.1103/PhysRevC.68.064302
2003TE03 Phys.Rev. C 67, 064314 (2003) E.Teran, V.E.Oberacker, A.S.Umar Axially symmetric Hartree-Fock-Bogoliubov calculations for nuclei near the drip lines NUCLEAR STRUCTURE 22O, 102Zr, 150Sn; calculated binding energies, pair gap energies, radii. Hartree-Fock-Bogoliubov approach, continuum coupling.
doi: 10.1103/PhysRevC.67.064314
2002TE18 Acta Phys.Hung.N.S. 16, 437 (2002) E.Teran, V.E.Oberacker, A.S.Umar Theoretical Description of Hartree-Fock Calculations under Axial Symmetry: First Results on Tin Isotopes NUCLEAR STRUCTURE 120,150Sn; calculated binding energies, pair gaps, deformation. Comparison with data.
doi: 10.1556/APH.16.2002.1-4.46
2002TO06 Phys.Rev. C65, 037601 (2002) Fusion Window Problem in Time-Dependent Hartree-Fock Theory Revisited NUCLEAR REACTIONS 16O(16O, X), 22O(22O, X), E(cm) ≈ 30-80 MeV; calculated fusion threshold energies for various model assumptions. Time-dependent density-matrix theory.
doi: 10.1103/PhysRevC.65.037601
2002TO20 Phys.Lett. 549B, 72 (2002) Quadrupole Resonances in Unstable Oxygen Isotopes in Time-Dependent Density-Matrix Formalism NUCLEAR STRUCTURE 22,24O; calculated quadrupole resonance strength distributions. Time-dependent density-matrix theory.
doi: 10.1016/S0370-2693(02)02885-X
2001MA09 Phys.Rev. C63, 024902 (2001) D.E.Malov, A.S.Umar, D.J.Ernst, D.J.Dean Relativistic Heavy-Ion Collisions in the Dynamical String-Parton Model NUCLEAR REACTIONS S, 197Au(p, X), E=200 GeV; S(S, X), E=200 GeV/nucleon; Pb(Pb, X), E=156 GeV/nucleon; calculated fragment rapidity distributions. Dynamical string-parton model, comparisons with data.
doi: 10.1103/PhysRevC.63.024902
2000ER11 Acta Phys.Hung.N.S. 11, 239 (2000) D.J.Ernst, D.E.Malov, A.S.Umar Classical Strings and Relativistic Heavy-Ion Collisions NUCLEAR REACTIONS 1H(p, X), E(cm)=30.4 GeV; S, Ar, Au(p, X), E=200 GeV/nucleon; S(S, X), E=200 GeV/nucleon; calculated multiplicity and rapidity distributions. Comparison with data. String-parton model.
1999GU10 Ann.Phys.(New York) 272, 7 (1999) M.C.Guclu, J.Li, A.S.Umar, D.J.Ernst, M.R.Strayer Electromagnetic Lepton-Pair Production in Relativistic Heavy-Ion Collisions NUCLEAR REACTIONS Pb(Pb, X), E=160 GeV/nucleon; 197Au(S, X), E=200 GeV/nucleon; calculated lepton pair production σ(E); deduced impact parameter dependence. Two-photon external filed model, hybrid Monte Carlo technique. Comparison with data.
doi: 10.1006/aphy.1998.5876
1999MA17 Phys.Rev. C59, 2289 (1999) D.E.Malov, A.S.Umar, D.J.Ernst, D.J.Dean Hadronic Structure Functions as Distributions of Classical Strings
doi: 10.1103/PhysRevC.59.2289
1999MA74 Int.J.Mod.Phys. E8, 299 (1999) D.E.Malov, A.S.Umar, D.J.Ernst, D.J.Dean Particle Identification in the Dynamical String-Parton Model of Relativistic Heavy-Ion Collisions
doi: 10.1142/S0218301399000215
1996CH31 Phys.Rep. 264, 107 (1996) C.R.Chinn, A.S.Umar, M.Vallieres, M.R.Strayer Mean Field Studies of Exotic Nuclei NUCLEAR STRUCTURE 16O; calculated isoscalar axial quadrupole moment fluctuations vs time, isoscalar octupole moment response function. Mean field approach.
doi: 10.1016/0370-1573(95)00031-3
1996NA03 Phys.Rev. C53, 740 (1996) W.Nazarewicz, J.Dobaczewski, T.R.Werner, J.A.Maruhn, P.-G.Reinhard, K.Rutz, C.R.Chinn, A.S.Umar, M.R.Strayer Structure of Proton Drip-Line Nuclei Around Doubly Magic 48Ni NUCLEAR STRUCTURE 42,44Cr, 46,48Fe, 48,50Ni; calculated 2-proton separation energies, deformations, single-particle levels, diproton partial decay T1/2. Self-consistent, relativistic mean-field theories.
doi: 10.1103/PhysRevC.53.740
1996WE02 Nucl.Phys. A597, 327 (1996) T.R.Werner, J.A.Sheikh, M.Misu, W.Nazarewicz, J.Rikovska, K.Heeger, A.S.Umar, M.R.Strayer Ground-State Properties of Exotic Si, S, Ar and Ca Isotopes NUCLEAR STRUCTURE 28,30Si, 32,34,36S, 36,40Ar, 40,42,44,46,48Ca; calculated rms charge radius. Self-consistent.
doi: 10.1016/0375-9474(95)00476-9
1995WE16 Nucl.Instrum.Methods Phys.Res. B99, 293 (1995) J.C.Wells, V.E.Oberacker, M.R.Strayer, A.S.Umar Lattice Calculation for Lepton Capture from Vacuum-Pair Production in Relativistic Heavy-Ion Collisions NUCLEAR REACTIONS 197Au(197Au, X), E=2 GeV/nucleon; calculated muon-pair production associated K-shell capture probabilities, relativistic collisions. Lattice collocation techniques, time-dependent Dirac equation.
doi: 10.1016/0168-583X(94)00652-0
1994WE11 Phys.Lett. 335B, 259 (1994) T.R.Werner, J.A.Sheikh, W.Nazarewicz, M.R.Strayer, A.S.Umar, M.Misu Shape Coexistence Around 4416S28: The deformed N = 28 region NUCLEAR STRUCTURE 28,30,32,34,36,38,40,42,44,46,48,50,52,54S; analyzed two-neutron separation energies, masses, deformations, radii, single particle level energies; deduced stability features around 44S.
doi: 10.1016/0370-2693(94)90347-6
1994WE16 Phys.Lett. 333B, 303 (1994) T.R.Werner, J.A.Sheikh, W.Nazarewicz, M.R.Strayer, A.S.Umar, M.Misu Shape Coexistence Around 4416S28: The deformed N = 28 Region NUCLEAR STRUCTURE 28,30,32,34,36,38,40,42,44,46,48,50,52S; calculated two-neutron separation energies, quadrupole mass deformations, neutron distribution rms radii. Self-consistent mean field theory.
doi: 10.1016/0370-2693(94)90146-5
1993DE48 Int.J.Mod.Phys. E2, 565 (1993) D.J.Dean, A.S.Umar, M.R.Strayer Dynamical Calculation of Central Energy Densities in Relativistic Heavy-Ion Collisions NUCLEAR REACTIONS O(O, X), S(S, X), E=200 GeV/nucleon; calculated central meson density vs time, thermodynamic quantities vs scaled energy density, relativistic collisions. String-parton model.
doi: 10.1142/S0218301393000224
1993OB02 Phys.Rev. C48, 1297 (1993) V.E.Oberacker, A.S.Umar, J.C.Wells, C.Bottcher, M.R.Strayer, J.A.Maruhn Muon-Induced Fission: A probe for nuclear dissipation and fission dynamics NUCLEAR STRUCTURE 238U; calculated mesonic atom levels, Coulomb interaction potential; deduced muon induced fission features. ATOMIC PHYSICS, Mesic-Atoms 238U; calculated mesonic atom levels, Coulomb interaction potential; deduced muon induced fission features.
doi: 10.1103/PhysRevC.48.1297
1992OB03 Phys.Lett. 293B, 270 (1992) V.E.Oberacker, A.S.Umar, J.C.Wells, M.R.Strayer, C.Bottcher Study of Nuclear Dissipation via Muon-Induced Fission. A Relativistic Lattice Calculation NUCLEAR REACTIONS 238U(μ-, F), E at rest; calculated muon-nucleus Coulomb interaction vs time during fission, muon to light fission fragment attachment probability vs dissipated energy. Relativistic lattice calculation.
doi: 10.1016/0370-2693(92)90882-5
1991UM01 Phys.Rev. C44, 2512 (1991) A.S.Umar, M.R.Strayer, J.-S.Wu, D.J.Dean, M.C.Guclu Nuclear Hartree-Fock Calculations with Splines NUCLEAR STRUCTURE 16O, 40Ca; calculated Hartree-Fock energies, n-, p-single particle energies. Spline collocation method.
doi: 10.1103/PhysRevC.44.2512
1989DE27 Phys.Rev. C40, 1213 (1989) D.J.Dean, A.S.Umar, M.R.Strayer Velocity Dependence of Prompt, High-Energy Nucleon Emission NUCLEAR REACTIONS 165Ho(58Ni, X), E=930 MeV; 93Nb(16O, X), E=204 MeV; calculated velocity, exit channel kinetic energy correlation for high energy nucleon emission. Time-dependent entrance channel formalism.
doi: 10.1103/PhysRevC.40.1213
1987LE21 Phys.Lett. 196B, 419 (1987) S.-J.Lee, A.S.Umar, K.T.R.Davies, M.R.Strayer, P.-G.Reinhard Enhanced Dissipation in New Mean-Field Studies of Strongly Damped Collisions NUCLEAR REACTIONS 139La(86Kr, X), E=610 MeV; calculated σ(fragment θ, E), rms radii, deflection function, kinetic energy. Time-dependent Hartree-Fock approximation.
doi: 10.1016/0370-2693(87)90793-3
1986LE16 Phys.Rev.Lett. 57, 2916 (1986); Erratum Phys.Rev.Lett. 59, 1171 (1987) S.-J.Lee, J.Fink, A.B.Balantekin, M.R.Strayer, A.S.Umar, P.-G.Reinhard, J.A.Maruhn, W.Greiner Relativistic Hartree Calculations for Axially Deformed Nuclei NUCLEAR STRUCTURE 12C, 16O, 20Ne, 24Mg, 40,48Ca; calculated binding energies, quadrupole moments. Relativistic Hartree calculations.
doi: 10.1103/PhysRevLett.57.2916
1986UM01 Phys.Lett. 171B, 353 (1986) Nuclear Shape-Isomeric Vibrations NUCLEAR STRUCTURE 24Mg; calculated isomer time evolution radius; deduced ion-ion collision correlated resonance source.
doi: 10.1016/0370-2693(86)91419-X
1986UM02 Phys.Rev.Lett. 56, 2793 (1986) A.S.Umar, M.R.Strayer, P.-G.Reinhard Resolution of the Fusion Window Anomaly in Heavy-Ion Collisions NUCLEAR REACTIONS 16O(16O, X), E(cm)=20, 34 MeV; calculated fusion σ. 16O(16O, 16O'), E=27-68 MeV; calculated inelastic thresholds; deduced spin-orbit interaction role. TDHF, Skyrme forces, spin-orbit interaction.
doi: 10.1103/PhysRevLett.56.2793
1985UM01 Phys.Rev. C32, 172 (1985) A.S.Umar, M.R.Strayer, R.Y.Cusson, P.-G.Reinhard, D.A.Bromley Time-Dependent Hartree-Fock Calculations of 4He + 14C, 12C + 12C(0+), and 4He + 20Ne Molecular Formations NUCLEAR REACTIONS 14C, 20Ne(α, α), 12C(12C, 12C), E ≈ Coulomb barrier; calculated composite system density contours, isoscalar quadrupole, octupole, isovector dipole moment frequency dependence; deduced dynamical degrees of freedom, associated classical frequencies. TDHF.
doi: 10.1103/PhysRevC.32.172
1984ST02 Phys.Lett. 135B, 261 (1984) M.R.Strayer, R.Y.Cusson, A.S.Umar, P.-G.Reinhard, D.A.Bromley, W.Greiner Time-Dependent Hartree-Fock Picture of Nuclear Molecular Resonances NUCLEAR STRUCTURE 18O; calculated isovector dipole, isocalar quadrupole, octupole molecular resonances. TDHF method.
doi: 10.1016/0370-2693(84)90387-3
1984UM02 Phys.Lett. 140B, 290 (1984) A.S.Umar, M.R.Strayer, D.J.Ernst A Time-Dependent External-Field Model for Particle Emission in Heavy-Ion Reactions NUCLEAR REACTIONS 93Nb(16O, nX), E=204 MeV; calculated inclusive nonequilibrium neutron emission probability vs t. Time-dependent external field model.
doi: 10.1016/0370-2693(84)90755-X
1984UM05 Phys.Rev. C30, 1934 (1984) A.S.Umar, M.R.Strayer, D.J.Ernst, K.R.Sandhya Devi Mean-Field Theory of Prompt, High-Energy Nucleon Emission NUCLEAR REACTIONS 93Nb(16O, X), E=204 MeV; calculated σ(θn, En) following fragment neutron emission. Time-dependent mean field theory.
doi: 10.1103/PhysRevC.30.1934
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