Experimental evidence for chirality in the odd-A 105Rh

High-spin states in Rh-105 were populated by the Zr-96(C-13,p3n) reaction at beam energies of 51 and 58 MeV, and studied using the EUROBALL IV gamma-ray spectrometer and the DIAMANT charged particle array. A pair of nearly degenerate DeltaI = 1 three-quasiparticle bands with the same spins and parity have been observed. Comparison of the experimental results with tilted axis cranking calculations confirms the chiral character of the two bands, while arguments based on the excitation of particles within the pig(9/2)nu(h(11/2))(2) configuration of the yrast band and comparison with the previously observed gamma band exclude the other possible interpretations. This is the first experimental evidence for three-quasiparticle chiral structure in the A similar to 100 region, and the first simultaneous observation of a gamma band and chiral partner bands in one nucleus. (C) 2004 Elsevier B.V. All rights reserved.