The forward-backward asymmetry and differences of partial moments in inclusive semileptonic B decays

Global fits to moments of kinematic distributions measured in inclusive semileptonic B -> Xcl nu l enable the determination of the Cabibbo-Kobayashi-Maskawa matrix ele-ment |Vcb| together with non-perturbative matrix elements of the heavy quark expan-sion. In current fits, only two distinct kinematic distributions are employed and, as a consequence, higher moments of these distributions need to be taken into account to extract the relevant non-perturbative matrix elements. The moments of a given dis-tribution are highly correlated and experimental uncertainties increase for higher mo-ments. To address these issues, Turczyk suggested the inclusion of the charged lepton forward-backward asymmetry AFB in global fits, since it provides information on non-perturbative parameters beyond the commonly used moments. It is possible to construct differences of partial moments of kinematic distributions, which can provide additional information on the non-perturbative parameters beyond AFB and are studied in this work for the first time. Further, experimental cuts on the four-momentum transfer square are studied and are shown to preserve the shape of the angular distribution, in contrast to commonly used cuts on the lepton energy. Finally, the impact of final-state radiation and experimental lepton identification requirements on measurements of AFB and dif-ferences of partial moments are discussed.