Evidence of antimagnetic rotation in odd-A 105Cd

The lifetimes of the levels above spin 23/2(-) in the negative-parity yrast band of Cd-105 have been measured using the Doppler shift attenuation method. The obtained B(E2) values are small and show a decrease with an increase in spin. This establishes, for the first time, antimagnetic rotation (AMR) in an odd-A nucleus. An excellent agreement between the theoretical (semiclassical model) and experimental results along with a large F-(2)/B(E2) ratio for the states strongly suggests that the structure of the levels beyond spin 23/2(-) has the character of a twin-shears type AMR band resulting from the coupling of a pair of g(9/2) proton holes with aligned h(11/2) and (g(7/2))(2) neutron particles, along with a small contribution from the core rotation.