Anomalous dimensions of high-twist operators in QCD at N → 1 and large Q2

Abstract

The anomalous dimensions of high-twist operators in deeply inelastic scattering ( γ 2 n ) are calculated in the limit when the moment variable N → 1 (or x B → 0) and at large Q 2 (the double logarithmic approximation) in perturbative QCD. We find that the value of γ 2 n × ( N − 1) in this approximation behaves as [N c α S /π(N − 1)]n 2 [1 + 1 3 δ(n 2 − 1)] where δ ≈ −2 . This implies that the contributions of the high-twist operators give rise to an earlier onset of shadowing than was estimated before. The derivation makes use of a Pomeron exchange approximation, with the Pomerons interacting attractively. We find that they behave as a system of fermions.