Münster 2002 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 30: Nuclear Physics / Spectroscopy IV

HK 30.4: Talk

Wednesday, March 13, 2002, 15:00–15:15, B

Magnetic and collective rotation in ⁷⁹Br — •F. Dönau¹, R. Schwengner¹, T. Servene¹, H. Schnare¹, J. Reif¹, G. Winter¹, L. Käubler¹, H. Prade¹, S. Skoda², J. Eberth², H.G. Thomas², F. Becker², B. Fiedler², S. Freund², S. Kasemann², T. Steinhardt², O. Thelen², T. Härtlein³, C. Ender³, F. Köck³, P. Reiter³, and D. Schwalm³ — ¹FZ Rossendorf — ²Universität Köln — ³MPI Heidelberg

Excited states of the nucleus ⁷⁹Br were investigated via the reaction ⁷⁶Ge(⁷Li,4n) at 35 MeV. A magnetic dipole (M1) band starting at J^π = 15/2⁻ was observed up to J^π = (29/2⁻). Mean lifetimes were deduced for most of the levels of the M1 band. We have interpreted the M1 band by applying the hybrid version of the Tilted-Axis-Cranking (TAC) model together with the shell-correction method. The Total Routhian Surfaces calculated within the TAC model predict a substantial triaxial deformation for the excited 3qp configuration π (g_9/2) ν (g_9/2) ν (fp) assigned to the M1 band. The comparison of experimental characteristics with predictions of the TAC calculations shows that the M1 band can be described by this tilted configuration which implies a strong magnetic component. On the other hand, considerable contributions of the collective spin are necessary to generate high spin. The M1 band is therefore considered as a band including components of both, magnetic and electric rotation.