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HK: Physik der Hadronen und Kerne

HK 10: Kernphysik/Spektroskopie

HK 10.8: Vortrag

Freitag, 4. März 2005, 18:45–19:00, TU MA005

Gamow-Teller strength distributions relevant for supernova modelling measured thru the (d,²He) reaction — •Sönke Hollstein, C. Bäumer, D. Frekers, E.-W. Grewe, and S. Rakers — Institut für Kernphysik, Westfälische-Wilhelms-Universität, Münster, Germany

In the explosion dynamics of supernovae electron capture (EC) processes on pf-shell nuclei play an important role. Gamow-Teller (GT) strength distributions for the pf-shell target nuclei ⁵⁷Fe, ⁶¹Ni, and ⁶⁷Zn have been measured by means of the (d,²He) reaction [1] at an energy of E_d=180 MeV using the BBS-ESN setup at the AGOR cyclotron facility at KVI, Groningen. Energy resolutions ranged between 100 and 120 keV. The interest in the odd-N nuclei originates from the fact that in the Fuller-Fowler-Newman parameterizaton [2] of the weak EC process the centroid GT resonance energies are by and large located at about 1 to 2 MeV higher than what recent large shell model (SM) calculations predict, with the exception of ⁶¹Ni where it is vice versa. The centroid position of the GT resonance is a more sensitive parameter of the deleptonization process in supernova modeling codes than e.g. the details of the distribution. In order to solve that issue our data will be compared to the most recent SM calculations [3] for these nuclei.

[1] S.Rakers et. al., Nucl. Instr. Meth. A 481, 253 (2002); C.Bäumer et. al., Phys. Rev. C 68, 031303R (2003).

[2] G.M. Fuller, W.A. Fowler, and M.J. Newman, Astrophys. J., Suppl. 252, 715 (1982) and references therein.

[3] K.Langanke et. al. Nucl. Phys A 673, 481 (2000).