Possible 'stapler' band in(109)Ag nucleus

High-spin states of Ag-109 have been studied using the Li-7 + Pd-110 reaction at a beam energy of 46 MeV. A negative-parity band decaying to the ground-state band by several new linking transitions is established. Meanwhile, seven new E2 crossover transitions of this band are observed, thereby confirming the spinparity assignment and ordering of the dipole transitions above the I-pi = 19/2(-) level. A low energy gamma-ray transition of 88 keV is found and placed at the bottom of the negative-parity band, and thus the I-pi = 17/2(-) level is tentatively assigned as the lowest observed state of this band. Experimental excitation energies and total angular momenta of the negative-parity band are compared with the predictions of self-consistent titled axis cranking relativisticmean-field theory with a three-quasiparticle configuration of pi g(9/2)(-1) circle times nu h(11/2)(g(7/2)/d(5/2))(-1). Based on the theoretical description and the analyses of the angular momentum coupling, this negative-parity dipole band is suggested as a `stapler' band. By investigating the angular momentum components, it is found that the valence nucleons in the low-j orbitals play an active role in the `stapler' mechanism.