A novel observable measuring the CP asymmetry in multi-body decays of heavy mesons, which is called the forward-backward asymmetry induced CP asymmetry (FBI-CPA), A(CP)(FB), is introduced. This observable has the dual advantages that 1) it can isolate the CP asymmetry associated with the interference of the S- and P-wave amplitude from that associated with the S- or P-wave amplitude alone; 2) it can effectively almost double the statistics comparing to the conventionally defined regional CP asymmetry. We also suggest to perform the measurements of FBI-CPA in some three-body decay channels of c...
