Background: In the continuum-discretized coupled-channel method, a breakup cross section (BUX) is obtained as an admixture of several components of different channels in multichannel scattering. Purpose: Our goal is to propose an approximate way of decomposing the discretized BUX into components of each channel. This approximation is referred to as the "probability separation (P separation)."Method: As an example, we consider Be11 scattering by using the three-body model with core excitation (Be10+n+T, where T is a target). The structural part is constructed by the particle-rotor model and the reaction part is described by the distorted-wave Born approximation. Results: The validity of the P separation is tested by comparing with the exact calculation. The approximate way reproduces the exact BUXs well regardless of the configurations and/or the resonance positions of Be11. Conclusion: The method proposed here can be an alternative approach for decomposing discretized BUXs into components in four- or five-body scattering where the strict decomposition is hard to perform.
All Science Journal Classification (ASJC) codes