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HK: Physik der Hadronen und Kerne
HK 43: Theorie VIII
HK 43.2: Gruppenbericht
Donnerstag, 22. März 2001, 15:00–15:30, B
Mid-rapidity charge distribution in peripheral heavy ion collisions — •Klaus Morawetz1,2, Pavel Lipavský3, Jacques Normand2, Daniel Cussol2, Jean Colin2, and Bernard Tamain2 — 1Max-Planck-Institute for the Physics of Complex Systems, Noethnitzer Str. 38, 01187 Dresden, Germany — 2LPC-ISMRA, Bld Marechal Juin, 14050 Caen, France — 3Institute of Physics, Academy of Sciences, Cukrovarnická 10, 16200 Praha 6, Czech Republic
The charge density distribution with respect to the velocity of matter
produced in peripheral heavy ion reactions around Fermi energy is
investigated [1]. The experimental finding of enhancement of
mid-rapidity
matter shows the necessity to include correlations beyond BUU which
was performed in the framework of nonlocal kinetic theory [2] already
applied to heavy ion collisions in [4,6].
This kinetic theory takes the finite duration and size of particle
collision into account [3].
Different other
theoretical improvements are discussed. While the in-medium cross
section
changes the number of collisions, it leads the transferred energy
almost unchanged. In contrast the nonlocal scenario changes the energy
transferred during collisions and leads to an enhancement of
mid-rapidity matter. The renormalisation of quasiparticle energies
can be included in nonlocal scenarios [5] and leads
to a further enhancement of mid-rapidity matter distribution. This
renormalisation is accompanied by a
dynamical softening of the equation of state seen in longer
oscillation periods of the excited compressional collective mode. We
propose to include quasiparticle renormalisation by using the
Pauli-rejected collisions which circumvent the problem of back-flows in
Landau theory.
Using the maximum relative velocity of
projectile and target like fragments we associate experimental events
with
impact parameters of the simulations. For peripheral collisions we find
a reasonable agreement between experiment and theory. For more central
collisions the velocity damping is higher in one - body simulations than
observed experimentally which is due to missing cluster
formations in the used kinetic theory.
[1]
K. Morawetz, P. Lipavský, J. Normand, D. Cussol, J. Colin, B. Tamain,
Phys. Rev. C, nucl-th/0011045
[2]
V. Špička, P. Lipavský, and K. Morawetz, Phys. Lett. A
240, (1998), 160
[3]
K. Morawetz, V. Spička, P. Lipavský, H.N. Kwong,
Phys. Rev. C 59,6 (1999) 3052-3059
[4]
K. Morawetz, V. Špička, P. Lipavský, G. Kortemeyer,
Ch. Kuhrts, R. Nebauer, Phys. Rev. Lett. 82, (1999), 3767
[5]
P. Lipavský, V. Spička, K. Morawetz,
Phys. Rev. E 59 (1999) R1291-R1294 rap. comm.
[6]
K. Morawetz,
Phys. Rev. C 62, (2000) 44606