Saturation of Superconvergence Relations and Current-Algebra Sum Rules for Forward Amplitudes

Helicity Amplitudes and Sum Rules for Real and Virtual Photons

The spin structure of the nucleon in the resonance region is of particular interest to understand the rapid transition from resonance dominated coherent processes to incoherent processes of deep inelastic scattering (DIS) off the constituents. Here we present the results of the recently developed unitary isobar model (MAID) for the spin asymmetries, structure functions and relevant sum rules in...

Sum Rules from the Algebra of Fields

Vacuum Saturation Hypothesis and QCD Sum Rules 1

The accuracy of the vacuum saturation hypothesis is discussed using the examples of vacuum expectation values of four-quark operators and the parameter B, which determines the short-distance contribution to the K 0 − ¯ K 0 mixing. Some comments, related to a (relatively small) change of the updated result due to changes in the values of incorporated phenomenological parameters, are added.

Exclusive Decay Amplitudes from Light-Cone Sum Rules

We review recent developments in QCD sum rule applications to semileptonic B → π and D → π transitions. INTRODUCTION The ongoing experiments at the B factories allow measurements of B decays and CP violation with greatly improved precision (see e.g. [1]) which should be matched also on the theoretical side. The most difficult obstacle are the longdistance QCD effects playing an important, somet...

Second Class Current in QCD Sum Rules

Induced tensor charge of the nucleon gT , which originates from G-parity violation, is evaluated from QCD sum rules. We find that gT /gA with gA being the axial charge is −0.0152 ± 0.0053 which is proportional to u-d quark mass difference. This result is small compared to preliminary analysis of the experiment, but is consistent with the estimate in the MIT bag model. PACS numbers: 12.38.Lg, 14...