422 research outputs found
Production of multi-strangeness hypernuclei and the YN-interaction
We investigate for the first time the influence of hyperon-nucleon (YN)
interaction models on the strangeness dynamics of antiproton- and -nucleus
interactions. Of particular interest is the formation of bound
multi-strangeness hypermatter in reactions relevant for \panda. The main
features of two well-established microscopic approaches for YN-scattering are
first discussed and their results are then analysed such that they can be
applied in transport-theoretical simulations. The transport calculations for
reactions induced by antiproton beams on a primary target including also the
secondary cascade beams on a secondary target show a strong sensitivity on the
underlying YN-interaction. In particular, we predict the formation of
-hypernuclei with an observable sensitivity on the underlying
N-interaction. We conclude the importance of our studies for the
forthcoming research plans at FAIR.Comment: 13 pages, 5 figures. Accepted for publication in Physics Letters
Pygmy Quadrupole Resonance in Skin Nuclei
The electric quadrupole response is investigated theoretically by HFB and QPM
calculations along the Sn isotopic chain with special emphasis on excitations
above the first collective state and below the particle threshold. Depending on
the asymmetry, additional strength clustering as a group of states similar to
the known PDR mode is found. The spectral distributions and electric response
functions are discussed. The transition densities of these Pygmy Quadrupole
Resonances (PQR) states are closely related to the neutron excess and showing
special features being compatible with an oscillation of the neutron skin
against the nuclear core. These features may indicate a new nuclear quadrupole
mode connected to the skin configuration.Comment: 7 pages, 5 figures, updated figure
Meson Production on the Nucleon in the Giessen K-Matrix Approach
Meson production on the proton is described in a coupled channels K-matrix
approach. Both hadronic and photonic scenarios are taken into account on the
same theoretical footing. At tree-level the Born amplitudes are obtained from
an effective Lagrangian with phenomenologically adjustable coupling constants.
The spectral distributions, resonances and their width and the background
contributions are obtained within the same approach, thus accounting properly
for interference effects. Applications to omega- and associated strangeness
production on the proton are discussed.Comment: 11 pages, 6 Figures, Proc. Int. Workshop NSTAR 2005 at Tallahassee,
Fl., Oct. 200
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