Constraints on exclusive branching fractions ℬ_i(B^+→ X_c^il^+ν ) from moment measurements in inclusive B→ X_clν decays

an alternative to direct measurements, we extract the branching fractions ℬ_i(B^+→ X_c^il^+ν ) 1 with X_c^i=D,D^*,D_0,D'_1,D_1,D_2,D',D'^* and non-resonant final states (D^(*)π )_nr , from a fit to electron energy, hadronic mass and combined hadronic mass–energy moments measured in inclusive B→ X_clν decays. The fit is performed by constraining the sum of exclusive branching fractions to the measured ℬ (B^+→ X_c l^+ν ) value, and with different sets of additional constraints for the directly measured branching fractions. There is no fit scenario in which a single branching fraction can close the gap between ℬ (B^+→ X_c l^+ν ) and the sum of known branching fractions ℬ_i(B^+→ X_c^il^+ν ) . The fitted ℬ(B^+→D^*0l^+ν ) is found to be significantly larger than its direct measurement. ℬ(B^+→D^0l^+ν ) is in good agreement with the direct measurement; when ℬ(B^+→D^*0 l^+ν ) is constrained the fitted ℬ(B^+→D^0l^+ν ) increases. Within large uncertainties, ℬ(B^+→D'^0_1l^+ν ) agrees with direct measurements. Depending on the fit scenario, ℬ(B^+→D^0_0l^+ν ) is consistent with or larger than its direct measurement. The fit is not able to easily disentangle B^+→D^0_1l^+ν and B^+→D^0_2l^+ν , and tends to increase the sum of these two branching fractions. ℬ (B^+→ (D^(*)π )_nrl^+ν ) with non-resonant (D^(*)π )_nr final states is found to be of the order 0.3 % . No indication is found for significant contributions from so far unmeasured B^+→D'^(*)0l^+ν decays.