Lishui Univ, Dept Phys, Zhejiang 323000, Peoples R China
; Shanghai Jiao Tong Univ, Dept Phys, Shanghai 200030, Peoples R China
; CCAST, World Lab, Beijing 100080, Peoples R China
; CAS, Inst High Energy Phys, Beijing 100049, Peoples R China
We study the rare decays B-s(0)-> D(+/-)pi(-/+) and (B) over bar (0)(s)-> D(-/+)pi(+/-), which can occur only via annihilation type W exchange diagrams in the standard model. The time-dependent decay rates of the four channels can provide four CP parameters, which are experimentally measurable. We show that the Cabibbo-Kobayashi-Maskawa angle phi(3)=gamma can be determined from these parameters without any theoretical model dependence. These channels can be measured in future LHCb experiments to provide a clean way for gamma measurement.