Speaker
Dr
Alexander Herlert
(European Organization for Nuclear Research (CERN))
Description
Nucleosynthesis theory describes how elements and nuclides are formed in stellar
evolution, e.g., violent processes like supernovae explosions. For the calculations
of the various pathways from hydrogen to the heavier elements the nuclear properties
of a large number of nuclides need to be known [1,2]. Especially in the case of the
r-process, where elements heavier than iron are formed by rapid neutron capture,
nuclear structure data of neutron-rich nuclides far from the valley of stability are
required.
The path of the r-process is determined by and reflects nuclear structure. For
example at the neutron shell N=50 it crosses through the waiting point nuclide 80Zn.
Slight deviations in the nuclear physics parameters can lead to large discrepancies
in the modeling of the subsequent nucleosynthesis processes. One crucial parameter is
the mass of the nuclides, which enters the determination of neutron separation
energies and the Q-values for the beta decays. They are thus essential for the study
of the r-process.
With the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN very precise and
accurate mass measurements with relative mass uncertainties down to dm/m=8x10-9 can
be achieved. Recently, the atomic masses of the neutron-rich zinc isotopes 71-81Zn
have been measured. For the first time the masses of 79Zn and 81Zn have been
determined. The new experimental data allow the investigation of nuclear structure at
the neutron shell N=50 for low Z. The possible impact on nuclear astrophysics is
discussed.
[1] M. Mukherjee et al., Phys. Rev. 93, 150801 (2004)
[2] D. Rodriguez et al., Phys. Rev. Lett. 93, 161104 (2004)
Author
Dr
Alexander Herlert
(European Organization for Nuclear Research (CERN))
Co-authors
Mr
Chabouh Yazidjian
(GSI)
Dr
Céline Guénaut
(CSNSM-IN2P3-CNRS)
Dr
Frank Herfurth
(GSI)
Prof.
H.-Jürgen Kluge
(GSI)
Dr
Klaus Blaum
(Johannes Gutenberg-University Mainz)
Prof.
Lutz Schweikhard
(Ernst-Moritz-Arndt-University Greifswald)
Mr
Michael Dworschak
(Johannes Gutenberg-University Mainz)
Mr
Sebastian George
(Johannes Gutenberg-University Mainz)
Mr
Sudarshan Baruah
(Ernst-Moritz-Arndt-University Greifswald)
Ms
Ulrike Hager
(University of Jyväskylä)
