Regge Cuts in QCD

-At high energies and limited transverse momenta, the amplitudes of QCD processes in the leading logarithmic approximation (LLA) are determined by the Regge pole with gluon quantum numbers and a negative signature. This property, called gluon reggeization, is extremely important for a theoretical description of high-energy processes in QCD. In particular, it underlies the derivation of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation. The pole Regge form is also preserved in the next-to-leading logarithmic approximation (NLLA). However, this form is violated in higher approximations. It is natural to assume that it is violated by the contributions of the Regge cuts. The structure of these cuts and its difference from the structure of cuts in the old (before QCD) theory of complex angular momenta is discussed.