2 research outputs found
Antikaon production in A+A collisions at SIS energies within an off-shell G-matrix approach
The production and propagation of antikaons -- described by dynamical
spectral functions as evaluated from a coupled channel
-matrix approach -- is studied for nucleus-nucleus collisions at SIS
energies in comparison to the conventional quasi-particle limit and the
available experimental data using off-shell transport theory. We find that the
spectra for and at 1.8 AGeV
remain underestimated in the -matrix approach as in the on-shell
quasi-particle approximation whereas the preliminary spectra for at
1.5 AGeV are well described in both limits. This also holds
approximately for the rapidity distributions in semi-central collisions
of at 1.93 AGeV. However, in all limits considered there is no
convincing description of all spectra simultaneously. Our off-shell transport
calculations, furthermore, demonstrate that the strongest in-medium effects
should be found for low antikaon momenta in the center-of-mass frame, since the
deceleration of the antikaons in the attractive Coulomb and nuclear potentials
and the propagation to the on-shell mass induces a net shift and squeezing of
the spectra to the low momentum regime.Comment: 44 pages, including 18 eps figures, to be published in Nucl. Phys.