arXiv subjects
Publications and source records attributed to B. Postler.
Deep virtual vector meson leptoproduction at small $\xbj$ is analyzed in the framework of generalized parton distributions. It is shown that the inclusion of transverse degrees of freedom leads to reasonable agreement with the cross section data for light mesons.
We present a status report on a study of vector meson leptoproduction for the HERA energy range on the basis of the generalized handbag approach. In contrast to the leading twist approach transverse degrees of freedom as well as Sudakov suppressions are taken into account in the subprocess. First results for the cross section for photoproduction of longitudinally polarized rho-mesons are found to be in fair agreement with experiment.
The hadronic mass distribution in semileptonic B-meson decays can be used for extracting the charmless part and thus determining the |V_ub/V_cb| ratio. We take into account first-order perturbative as well as non-perturbative QCD corrections. The sensitivity to model assumptions is studied and an estimate of the remaining uncertainties is performed.
We obtain model independent bounds for the form factors which arise in semileptonic B -> Pi decays. To this end we derive a theoretical restriction for possible combinations of the value of the form factor and its derivatives at the endpoint region. These restrictions are then used as an input in a - slightly modified - general formalism, which has already been deduced and applied in earlier publications. Our results can be used to set constraints on the form factors which have to be obeyed by all model dependent parametrizations.