Impact parameter dependence of collective flows and particle multiplicities in heavy-ion reactions

Abstract

AbslracLWe sludy the impact parameter dependence of mllective flows and panicle multiplicities in h e a y i o n reactions from 84-2100 MeV A -' . W e consider mainly the 'Oca +' ' Ca system. For mmparison with experimental data other synems are also considered. When the bombarding energies arc M o w 400 MeV A-', we use the quantum molecular dynamics (QMD) with the nucleon-nucleon moss seclion obtained from Ihe G-matrix. At bombarding energies in the GeV A-' region, we use relativislic quantum molecular dynamics (RQMD) with the Cugnon paramelrilalion for lhe taryonbaryon cross seclions. We calculate the degree of equilibrium, the directed transveme m~xen!fim mr! the ~lpidi!;, dir!rih!!tioE. >,E mc!!ip!icitirs of photons, pions, e 0 5 ezd hons are also calculated and analysed. Their dependence on lhe nuclear equation of slate Vr studied in detail. lhere Is fair agreement between Ihe theoretical mulls and experimental data for panicle produclion c m s seclions and mulliplicities.

Subthreshold kaon production and the nuclear equation of state

“…In the non-relativistic Boltzmann-Uehling-Uhlenbeck (BUU) model, they found that in central heavy ion collisions at an incident energy of 0.7 GeV/nucleon the kaon yield obtained with a soft EOS (compressibility K=200 MeV) was about 2-3 times larger than that obtained with a stiff EOS (K=380 MeV). This finding was later confirmed in calculations based on the quantum molecular dynamics (QMD) [2,3].…”

Microscopic calculation of in-medium nucleon-nucleon cross sections

“…Specifically, in-medium total as well as differential NN cross sections are needed by these models in dealing with the in-medium NN scattering using a Monte Carlo method. Moreover, if these models are used to calculate the spectrum of particles produced in heavy-ion collisions, such as photons, pions and kaons, one also needs to know the in-medium elementary particle production cross section [34,38,[42][43][44]; e.g., the in-medium cross section of neutron-proton (np) bremsstrahlung (np → npγ) is needed in the calculation of the photon production cross section in nucleus-nucleus collisions. Up till now, most calculations of particle production in nucleus-nucleus collisions are based on the free production cross sections.…”

K+ momentum spectrum from (K−, K+) reactions in the intranuclear cascade model

“…Furthermore, it becomes possible to describe the time-development of totally anti-symmetrized wave functions [33,35]. These extended versions of the INC model are called microscopic transport models or microscopic simulations, and they have been successful in studying various aspects of heavy-ion collisions as well as light-ion induced reactions -particle production [36,37,21,19], single-particle spectra [23], collective flow [16,35], and fragment production [27,30,34,38]. This paper is organized as follows: We describe our INC model in Sec.…”