ACAD SINICA,INST HIGH ENERGY PHYS,BEIJING 100039,PEOPLES R CHINA
; ACAD SINICA,INST THEORET PHYS,BEIJING 100080,PEOPLES R CHINA
; NANKAI UNIV,DEPT PHYS,TIANJIN 300071,PEOPLES R CHINA
The effect of the nuclear medium is considered in terms of an effective pion background field and a new way of evaluation is proposed. Namely, in the scattering of a kaon from a nucleon in the nuclear matter, the effect of the classical pion cloud is attributed to the individual nucleon through a background field term u(x) in the extended Dirac equation. By employing several ansatz for the pion field, the agreement between the calculated result and experimental data is obtained.