Magnetic and collective rotation in 79Br

Excited states of the nucleus Br-79 were investigated via the reaction Ge-76(Li-7,4n) at a beam energy of 35 MeV. Coincidence data of emitted gamma rays were measured with an arrangement of six EUROBALL CLUSTER detectors. The E2 bands built on the 9/2(+) and 3/2(-) states were extended up to J=37/2 at Eapproximate to8.8 MeV. The M1 band starting with a 15/2(-) state at 2.6 MeV was observed up to J=(29/2) at E=6.4 MeV. Crossover E2 transitions within this band were observed for the first time. Mean lifetimes of 17 levels were deduced using the Doppler-shift-attenuation method. The M1 band can be described within the tilted-axis-cranking model on the basis of the tilted three-quasiparticle configuration pi(g(9/2)) nu(g(9/2)) nu(fp) which has a triaxial shape. This band appears as a mixed case including contributions of both magnetic and collective rotation.