Second EMMI-EFES Workshop
on Neutron-Rich Nuclei

RIKEN Wako, June 16 - 18, 2010


| EENEN 10 | Program | Participants | Hotel |

ExtreMe Matter Institute EMMI
International Research Network for Exotic Femto Systems EFES
Second EMMI-EFES workshop on neutron-rich exotic nuclei EENEN 10
- Neutron-rich nuclear matter, nuclear structure and nuclear astrophysics -

16-18 June 2010, RIKEN Wako

The theoretical and experimental study of weakly bound neutron matter is essential for understanding processes in nuclear astrophysics like the synthesis of heavy elements, the physics of stellar explosions, the structure of compact objects like white dwarfs or neutron stars, or the thermonuclear explosions on their surfaces seen as novae or X-ray bursters. At high nuclear densities strangeness degrees of freedom can be populated. As one can not directly reproduce the stellar environment in the laboratory one has to resort to exotic neutron rich nuclei and hypernuclei and invoke nuclear structure models to extrapolate to the systems of interest that can not be addressed by the measurements.

We propose to concentrate on the following topics as they are closely related for the microscopic understanding of the extremes of nuclear matter:

Nuclear Astrophysics
Weakly bound neutron matter
Many-body methods
Hadron interactions
Perspectives of the field

In a microscopic ab initio treatment of the low-energy nuclear many-body problem the degrees of freedom are the c.m.-positions of the baryons and their internal degrees of freedom, like spin, isospin or strangeness. The derivation of the forces among the baryons from the underlying QCD in the framework of chiral perturbation theory has become the most promising approach. But also potentials based on meson exchange and phenomenological potentials are still in use. Common to all realistic potentials is the successful reproduction of the nucleon-nucleon scattering data including the T=1 neutron-neutron channel. These potentials together with suitable many-body approaches should therefore provide predictive power for exotic neutron-rich nuclei and help to set up reliable equations of state for neutron matter in the universe.

Recent developments in understanding of particular effects of specific components of nuclear forces, two-body and three-body, are opening new fields of the spectroscopy of neutron-rich nuclei in theoretical and experimental studies. We can now see more direct relations between the structure of neutron-rich nuclei and the nuclear forces. Such relations are further related to properties of neutron matter, including lower and higher densities.

In the strange sector of the baryons the hyperon-nucleon and hyperon-hyperon interaction is much less known than the one among nucleons. Here the study of hypernuclei can supplement the sparse scattering data and derivations based on QCD symmetries. Again reliable microscopic many-body models are needed in order to properly relate interactions in bound states and in scattering states.

There has been recently important progress in modeling nuclear input involving neutron-rich nuclei in different astrophysical environments. These involve weak-interaction rates for the matter composition during the collapse of a massive star leading to a supernova explosion, the modeling of the crust composition and its cooling for separated neutron stars and those in binaries accreting matter from the companion as well as in simulations of r-process nucleosynthesis. For the latter network codes have been developed which can be coupled to the astrophysical environment and which consistently take the relevant nuclear reactions including fission into account. Parameter studies point to the crucial nuclear inputs and define the needs from nuclear many-body models.

Experimental measurements of the dipole strength in very neutron rich nuclei have established the existence of an important enhancement of the strength at excitations energies noticeably lower than the centroid of the dipole giant resonance. Such enhanced strength can have interesting consequences for neutron capture cross sections needed in r-process simulations. These data may also serve as constraints for the nuclear symmetry energy with significant consequences for the structure of neutron stars.

The workshop will bring together experimentalists and theorists with expertise in nuclear structure, reactions, hypernuclei and nuclear astrophysics discussing the latest developments in the fields of nuclear physics and astrophysics with neutron rich nuclei and matter. The workshop will also investigate the possibility to establish further collaborations on the nuclear research objectives outlined above.

For further information and registration contact

Thomas Aumann, T.Aumann-at-gsi.de
Takaharu Otsuka, otsuka-at-phys.s.u-tokyo.ac.jp
Gabriel Martinez Pinedo, g.martinez-at-gsi.de or
Peter Ring, peter.ring-at-physik.tu-muenchen.de
Takashi Nakatsukasa, nakatsukasa-at-riken.jp
Shinichiro Fujii, sfujii-at-cns.s.u-tokyo.ac.jp
Last modified: April 27, 2010