In this paper we investigate the possibility of studying B→π form factor using the semi-inclusive decays B̅^0 →π^+ + X_q. In general B→ PX semi-inclusive decays involve several hadronic parameters. But for B̅^0 →π^+ X_q decays we find that in the factorization approximation, the only unknown hadronic parameters are the form factors F^B→π_0,1. Therefore these form factors can be studied in B̅^0 →π^+ X_q decays. Using theoretical model calculations for the form factors the branching ratios for

more »

... 0 →π^+ X_d(Δ S = 0) and B̅^0 →π^+ X_s (Δ S = -1), with the cut E_π > 2.1 GeV, are estimated to be in the ranges of (3.1∼ 4.9) × 10^-5(F^B→π_1(0)/0.33)^2 and (2.5∼ 4.2)× 10^-5(F_1^B→π(0)/0.33)^2, respectively, depending on the value of γ. The combined branching ratio for B̅^0 →π^+ (X_d+ X_s) is about 7.4× 10^-5 (F^B→π_1(0)/0.33)^2 and is insensitive to γ. We also discuss CP asymmetries in these decay modes.