Publications (34)
Primary fission fragment mass yields across the chart of nuclides
M. R. Mumpower, P. Jaffke, M. Verriere +1
We have calculated a complete set of primary fission fragment mass yields, , for heavy nuclei across the chart of nuclides, including those of particular relevance to the rap…
Effects of Spin-Isospin Modes in Transport Simulations
J. Helgesson, J. Randrup
In-medium properties derived for nuclear matter in a microscopic pi + nucleon-hole + delta-hole model are incorporated into transport simulations of nuclear collisions by means of…
Event-by-event evaluation of the prompt fission neutron spectrum from 239Pu(n, f)
R. Vogt, J. Randrup, D. A. Brown +2
Earlier studies of 239Pu(n, f) have been extended to incident neutron energies up to 20 MeV within the framework of the event-by-event fission model FREYA, into which we have incor…
Spin-Isospin Modes in Heavy-Ion Collisions I: Nuclear Matter at Finite Temperatures
J. Helgesson, J. Randrup
With a view towards implementation in microscopic transport simulations of heavy-ion collisions, the properties of spin-isospin modes are studied in nuclear matter consisting of nu…
Calculation of fission observables through event-by-event simulation
J. Randrup, R. Vogt
The increased interest in more exclusive fission observables has demanded more detailed models. We present here a new computational model, FREYA, that aims to meet this need by pro…
Baryon-strangeness correlations: a diagnostic of strongly interacting matter
V. Koch, A. Majumder, J. Randrup
The correlation between baryon number and strangeness elucidates the nature of strongly interacting matter, such as that formed transiently in high-energy nuclear collisions. This…
Study of angular momentum effects in fission
R. Vogt, J. Randrup
Background: The role of angular momentum in fission has long been discussed but the observable effects are difficult to quantify. Purpose: We discuss a variety of effects associate…
Amplification of pionic instabilities in high-energy collisions?
J. Randrup
Considering a variety of dynamical scenarios within the linear sigma model, we examine the conditions for pionic modes to be amplified as the chiral field relaxes towards the norma…
Baryon number and strangeness: signals of a deconfined antecedent
A. Majumder, V. Koch, J. Randrup
The correlation between baryon number and strangeness is used to discern the nature of the deconfined matter produced at vanishing chemical potential in high-energy nuclear collisi…
High resolution measurement of tagged two-neutron energy and angle correlations in Cf-252(sf)
P. F. Schuster, M. J. Marcath, S. Marin +9
Background: Spontaneous fission events emit prompt neutrons correlated with one another in emission angle and energy. Purpose: We explore the relationship in energy and angle betwe…
Improved modeling of photon observables with FREYA
R. Vogt, J. Randrup
The event-by-event fission model FREYA has been improved, in particular to address deficiencies in the calculation of photon observables. We discuss the improvements that have been…
Event-by-event study of prompt neutrons from 239Pu(n,f)
R. Vogt, J. Randrup, J. Pruet +1
Employing a recently developed Monte Carlo model, we study the fission of 240Pu induced by neutrons with energies from thermal to just below the threshold for second chance fission…
Correlated Prompt Fission Data in Transport Simulations
P. Talou, R. Vogt, J. Randrup +15
Detailed information on the fission process can be inferred from the observation, modeling and theoretical understanding of prompt fission neutron and -ray~observables. Beyond…
Quantum Fluctuation Effects on Nuclear Fragment Formation
A. Ohnishi, J. Randrup
Multifragmentation in Au+Au collisions is investigated at incident energies in the range 100-400 MeV per nucleon by means of a recently developed quantal Langevin model. The inclus…
Correlation studies of fission fragment neutron multiplicities
M. Albertsson, B. G. Carlsson, T. Døssing +3
We calculate neutron multiplicities from fission fragments with specified mass numbers for events having a specified total fragment kinetic energy. The shape evolution from the ini…
Microscopic treatment of energy partition in fission
M. Albertsson, B. G. Carlsson, T. Døssing +3
The transformation of an atomic nucleus into two excited fission fragments is modeled as a strongly damped evolution of the nuclear shape, until scission occurs at a small critical…
Analysis of Boltzmann-Langevin Dynamics in Nuclear Matter
S. Ayik, Ph. Chomaz, M. Colonna +1
The Boltzmann-Langevin dynamics of harmonic modes in nuclear matter is analyzed within linear-response theory, both with an elementary treatment and by using the frequency-dependen…
Dilepton from Disoriented Chiral Condensates
V. Koch, J. Randrup, X. N. Wang +1
Disoriented chiral condensates are manifested as long wavelength pionic oscillations and their interaction with the thermal environment can be a significant source of dileptons. We…
Transport Simulations with Pi and Delta In-Medium Properties
J. Helgesson, J. Randrup
Transport simulations including in-medium properties derived in a microscopic pi + nucleon-hole + delta-hole model in infinite nuclear matter are presented. In-medium pion dispersi…
Calculated fission-fragment mass yields and average total kinetic energies of heavy and superheavy nuclei
M. Albertsson, B. G. Carlsson, T. Døssing +3
Fission-fragment mass and total-kinetic-energy (TKE) distributions following fission of even-even nuclides in the region and , comprising 8…
Quantum fluctuation effects on hyperfragment formation from Xi^- absorption at rest on 12C
Y. Hirata, Y. Nara, A. Ohnishi +2
Formation mechanisms of single, twin, and double hypernuclei from Xi^- absorption at rest on 12C are investigated with an refined microscopic transport model, that incorporates the…
Event-by-event study of neutron observables in spontaneous and thermal fission
R. Vogt, J. Randrup
The event-by-event fission model FREYA is extended to spontaneous fission of actinides and a variety of neutron observables are studied for spontaneous fission and fission induced…
Enhanced Event-by-Event Fluctuations in Pion Multiplicity as a Signal of Disoriented Chiral Condensates at RHIC
M. Bleicher, J. Randrup, R. Snellings +1
The factorial moments of the pion multiplicity distributions are calculated with HIJING and UrQMD and found to be independent of the pT range included, in contrast to recent simula…
Fission-fragment mass distributions from strongly damped shape evolution
J. Randrup, P. Moller, A. J. Sierk
Random walks on five-dimensional potential-energy surfaces were recently found to yield fission-fragment mass distributions that are in remarkable agreement with experimental data.…
Quantum Fluctuations Affect the Critical Properties of Noble Gases
A. Ohnishi, J. Randrup
Interacting argon atoms are simulated with a recently developed quantum Langevin transport treatment that takes approximate account of the quantum fluctuations inherent in microsco…
Treatment of Pionic Modes at the Nuclear Surface for Transport Descriptions
J. Helgesson, J. Randrup
Dispersion relations and amplitudes of collective pionic modes are derived in a pi + nucleon-hole + delta-hole model for use in transport descriptions by means of a local density a…
Dynamical phase trajectories for relativistic nuclear collisions
I. C. Arsene, L. V. Bravina, W. Cassing +7
Central collisions of gold nuclei are simulated by several existing models and the central net baryon density rho and the energy density eps are extracted at successive times, for…
Inclusion of Quantum Fluctuations in Wave Packet Dynamics
A. Ohnishi, J. Randrup
We discuss a method by which quantum fluctuations can be included in microscopic transport models based on wave packets that are not energy eigenstates. By including the next-to-le…
Fission modes in fermium isotopes with Brownian shape-motion model
M. Albertsson, B. G. Carlsson, T. Døssing +3
Fission-fragment mass and total-kinetic-energy distributions following fission of the fermium isotopes at low excitation energy have been calculated using…
Exploring high-density baryonic matter: Maximum freeze-out density
J. Randrup, J. Cleymans
The hadronic freeze-out line is calculated in terms of the net baryon density and the energy density instead of the usual T and mu_B. This analysis makes it apparent that the freez…
Generation of fragment angular momentum in fission
J. Randrup, R. Vogt
A recent analysis of experimental data [J. Wilson , Nature , 566 (2021)] found that the angular momenta of nuclear fission fragments are uncorrelated. Based on…
Dileptons from Disoriented Chiral Condensates
Y. Kluger, V. Koch, J. Randrup +1
Disoriented chiral condensates or long wavelength pionic oscillations and their interaction with the thermal environment can be a significant source of dileptons. We calculate the…
Formation of transfermium elements in reactions with Pb
M. Albertsson, B. G. Carlsson, T. Døssing +3
Within the Langevin framework, we investigate the dynamics of the fusion process for production of transfermium elements in reactions of Ca, Ti, Cr, and $^{58}…
DCC dynamics with the SU(3) linear sigma model
J. Schaffner-Bielich, J. Randrup
The SU(3) extension of the linear sigma model is employed to elucidate the effect of including strangeness on the formation of disoriented chiral condensates. By means of a Hartree…