Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; China Inst Atom Energy, Beijing 102413, Peoples R China
; Natl Lab Heavy Ion Accelerator, Ctr Theoret Nucl Phys, Lanzhou 730000, Peoples R China
; Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China
The contribution of the resonant continuum to pairing correlations is investigated in the relativistic mean field theory plus Bardeen-Cooper-Schrieffer (BCS) approximation with a constant pairing strength. The resonance states with their widths in the continuum are considered explicitly. The numerical study is performed in an effective Lagrangian with the parameter set NLSH for neutron-rich nucleus Ni-84. The results show that the effect of the proper treatment of the resonant continuum on pairing correlations for nucleus close to neutron drip line is important. It is found that the problem of an unphysical particle gas could be overcome when the pairing correlation is performed by using the resonant states instead of the discretized states in the continuum.