FIAS Scientific Report 2011 - Frankfurt Institute for Advanced Studies ...

Applications of a chiral SU(3) model for the binding energies of nuclei, driplines of nuclei and
hyper-nuclei, and the mass-radius relation of neutron stars
Collaborators: T. Schürhoff 1,2 , S. Schramm 1 , C. Samanta 3,4
1 Frankfurt Institute for Advanced Studies, 2 Institute for Theoretical Physics (ITP), Goethe University, Frankfurt, 3 Saha
Institute of Nuclear Physics, Kolkata, India, 4 Department of Physics, Virginia Commonwealth University, Richmond,
VA, USA
One of the major goals in contemporary nuclear physics is the determination of the equation of state of hadronic
matter. This will allow for a great many applications, both on the experimental and theoretical side, for example
in supernova simulations. In order to theoretically study hadrons, we look at the binding energies of nuclei and
compare the results of our model with experimental results. We can reproduce the binding energies of nuclei
over the whole nuclide chart up to 0.7 % and work to improve our fitting parameters.
We also study the driplines of normal and hyper-nuclei and extrapolate to regions not experimentally accessible
at the moment. This is of interest for upcoming experiments at GSI. We find that the extrapolation of drip-lines
is very much model dependent.
In addition, we study the effect of the change of the fitting parameters of our model for the mass-radius relation
of neutron stars. There, parameter changes only have a very marginal effect.
Figure 1: The dripline determination of the hyper-nucleus Magnesium 40 containing one Λ hyperon. Plotted
is the the deformation β versus the total binding energy in MeV. The nucleus will move to the deformation
with the lowest binding energy, i.e. the minimum. The dripline is that nucleus for which the addition of further
particles, here neutrons, will no longer yield an increase in binding energy.
Related publications in 2011:
1) S. Schramm, V. Dexheimer, R. Negreiros, T. Schürhoff, Nuclear matter, nuclei and neutron stars in hadron
and and quark-hadron models, in Symposium on Advances in Nuclear Physics in our time, Goa, India, 28.
Nov. - 2. Dec. 2010, 2011. arXiv:1102.2325 [nucl-th].
2) S. Schramm, R. Negreiros, J. Steinheimer, T. Schürhoff, V. Dexheimer, Properties and stability of hybrid
stars, in Strangeness in Quark matter (SQM2011), Krakow, Poland, 18.-24. Sept. 2011. arXiv:1112.1853
[astro-ph.SR].
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