We present an improved calculation of all B → light pseudoscalar formfactors from light-cone sum rules, including one-loop radiative corrections to twist-2 and twist-3 contributions, and leading order twist-4 corrections. The total theoretical uncertainty of our results at zero momentum transfer is 10 to 13%. The dependence of the formfactors on the momentum transfer q 2 is parametrized in a si...

We study double spin asymmetries in Drell-Yan processes which one initial hadron is transversely polarized and another longitudinally polarized. The complete part of the hadronic tensor relevant to derived. This consists twist-2 twist-3 parton distributions gauge invariant. construct some observables can be used extract these from experimental measurements.

We discuss the spin-dependent structure function g2(x,Q ) in the framework of the operator product expansion. It is noted that the anomalous dimensions and coefficient functions for the twist-3 gluon-field-dependent operators depend on the choice of the operator basis. The role played by the operators proportional to the equation of motion is clarified. HUPD-9503 January, 1995

The transverse component of the axial-vector correlation function quark fields is a natural starting object for lattice calculations twist-3 nucleon parton distribution functions. In this work we derive corresponding factorization expression in terms twist-2 and collinear distributions to one-loop accuracy. results are presented both position space, as theorem Ioffe-time distributions, momentum...

In this letter we report the direct perturbative QCD evaluation of twist-4 effects in diffractive DIS. They are large and have a strong impact on the Q dependence of diffractive structure functions at large β. Based on the AGK rules, we comment on the possible contribution from diffractive higher twists to ∝ 1 Q corrections to proton structure function at small x. These corrections to the longi...

We review the possibility to use the renormalons emerging in the perturbation series of the twist-2 part of the nonsinglet structure functions F L , F 2 , F 3 , and g 1 to make approximate predictions for the magnitude of the appertaining twist-4 corrections.

After reviewing QCD definitions of the chiral-odd spin-dependent parton distributions h1(x,Q) and hL(x,Q 2), I will summarize the main feature of the recent two results in perturbative QCD: (i) Next-to-leading order Q2 evolution of h1(x,Q). (ii) Leading order Q2 evolution of the twist-3 distribution hL(x,Q 2) and the universal simplification of the Q2 evolution of all the twist-3 distributions ...

We present a derivation of Wandzura-Wilczek (WW) like relations for skewed par-ton distributions. It is demonstrated for photon-pion scattering that the skewed twist-3 parton distributions contributing to the DVCS amplitude have discontinuities at the points x = ±ξ in the WW approximation. This may lead to a violation of factorisation for the twist-3 DVCS amplitude with transverse polarization ...

We review the possibility to use the renormalons emerging in the perturbation series of the twist-2 part of the nonsinglet structure functions F L , F 2 , F 3 , and g 1 to make approximate predictions for the magnitude of the appertaining twist-4 corrections.