Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · nucl-th/9811015

Modelling the many-body dynamics of heavy ion collisions: Present status and future perspective

C. Hartnack·Rajeev K. Puri·J. Aichelin·J. Konopka·S. A. Bass·H. Stoecker·W. Greiner
View original source ↗Read source document ↗Export metadata ↓

Abstract

Basic problems of the semiclassical microscopic modelling of strongly interactingsystems are discussed within the framework of Quantum Molecular Dynamics (QMD). This model allows to study the influence of several types of nucleonic interactions on a large variety of observables and phenomena occurring in heavy ion collisions at relativistic energies.It is shown that the same predictions can be obtained with several -- numerically completely different and independently written -- programs as far as the same model parameters are employed and the same basic approximations are made. Many observables are robust against variations of the details of the model assumptions used. Some of the physical results, however, depend also on rather technical parameters like the preparation of the initial configuration in phase space. This crucial problem is connected with the description of the ground state of single nuclei,which differs among the various approaches. An outlook to an improved molecular dynamics scheme for heavy ion collisions is given.

Explore related subjects

nucl-th

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C. Hartnack, Rajeev K. Puri, J. Aichelin, J. Konopka, S. A. Bass, H. Stoecker, W. Greiner. 1998-11-04. Modelling the many-body dynamics of heavy ion collisions: Present status and future perspective. https://doi.org/10.1007/s100500050045

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Wigner distribution modeling of nuclear state in NuWro Monte Carlo event generator

We develop a method to use the Wigner distribution (WD) description of the nuclear initial state of $^{12}$C, $^{16}$O, $^{40}$Ar, and $^{56}$Fe for quasielastic scattering in the NuWro Monte Carlo event generator. We propose two different algorithms to deal with the problem of negative values of the WDs. In our treatment, finite-nucleus WDs provide a correlation between the position and the momentum of bound nucleons that is very different from what is assumed in the standard approaches based on the Fermi gas model and spectral functions. We show that the use of WDs leads to effects that can be measured experimentally and may be relevant for future neutrino oscillation experiments.

nucl-th↗
arXiv2026

Effects of in-medium $NN$ inelastic cross sections and the high-momentum tail of nucleon momentum distributions on pion production in heavy-ion collisions

Pion production in intermediate-energy heavy-ion collisions (HICs) provides a sensitive probe of the nuclear equation of state and of the isospin dependence of reaction dynamics. In particular, pion production near threshold is strongly affected by the nucleon-nucleon ($NN$) inelastic cross sections and by the high-momentum components of the nucleon momentum distribution. To explore the influence of these two ingredients on pion production and charged-pion ratios, the in-medium $NN$ inelastic cross sections calculated within the relativistic Boltzmann-Uehling-Uhlenbeck transport theory and the short-range correlation induced high-momentum tail (HMT) are introduced into the Ultra-relativistic Quantum Molecular Dynamics model. By simulating Au+Au collisions at intermediate energies, we find that the in-medium modification of the $NN$ inelastic cross sections suppresses the pion multiplicity by reducing the probability of $NΔ$ production in dense matter. The HMT, on the other hand, enhances the high-momentum components of nucleons and modifies the available energy in individual $NN$ collisions, thereby affecting $NN\rightarrow NΔ$ reactions and the subsequent pion production. With the simultaneous inclusion of these two effects, the pion yields and the $π^-/π^+$ ratio data can be better reproduced. These results highlight the importance of both the in-medium reaction cross sections and short-range correlation induced high-momentum components in pion production in intermediate energy HICs.

nucl-th↗
arXiv2026

Neutron star cooling with medium-modified Urca rates

We study the effects of in-medium modification of the elementary cooling processes on observable properties of isolated neutron stars. We deduce the neutron star mass distributions compatible with the cooling analysis and compare with current theoretical models. We conclude that current cooling data require fast direct Urca cooling, moderated by proton superfluidity, to be active in most neutron stars, and that the DU onset threshold must lie below canonical masses. In that case medium modifications of modified Urca rates are practically insignificant, but the nn Bremsstrahlung rate plays a dominant role.

nucl-th↗