QCD at high energies and Yangian symmetry

Yangian symmetric correlators provide a tool to investigate integrability features of QCD at high energies. We discuss the kernel of the equation of perturbative Regge asymptotics, the kernels of the evolution equation of parton distributions, Born scattering amplitudes and coupling renormalization.Comment: 11 pages, contribution to ICNFP18, published versio

Next-to-leading gluonic reggeons in the high-energy effective action

We study the next-to-leading gluon exchange in the high-energy scattering that contributes to the amplitude to order $s^0$ up to logarithmic corrections. Similar to the leading gluon exchange these contribution can be described in terms of reggeon exchanges. There are several gluonic reggeons at the next-to-leading level. Some of them transfer parity or gauge group representation different from the leading gluonic reggeon. Unlike the leading one they are sensitive to the helicity and transverse momenta of the scattering partons. We extend the high-energy effective action and derive from the action of gluodynamics the terms describing the next-to-leading reggeons and their interaction in the multi-Regge approximation.Comment: 31 pages in LATEX, 4 eps figures, references adde

Regge Asymptotics of Scattering with Flavour Exchange in QCD

The contribution to the perturbative Regge asymptotics of the exchange of two reggeized fermions with opposite helicity is investigated. The methods of conformal symmetry known for the case of gluon exchange are extended to this case where double-logarithmic contributions dominate the asymptotics. The Regge trajectories at large momentum transfer are calculated.Comment: 18 pages LATEX, 3 figures using package FEYNMAN, N3-9

Electroproduction of vector mesons - factorization of end-point contributions

The end-point contributions in the quark longitudinal momentum fraction of the virtual photon ($\gamma^*$) to vector meson ($V$) impact factor to the diffractive electroproduction amplitude can be factorized in terms of a generalized parton evolution of the target parton distribution. The result is used to model the helicity amplitudes $\gamma^* p \to V p$ in terms of small $x$ generalized parton distributions.Comment: 24 pages LaTex, 4 eps-figure

Symmetric reggeon interaction in perturbative QCD

Integral kernels describing the pair interaction of reggeized gluons and quarks are reconstructed in terms of conformal symmetric 4-point functions in the transverse plane of impact parameters.Comment: 13 pages, 3 figure

Gluonic reggeons

Contributions from gluon interactions, which are non-leading in high-energy semi-hard processes, are studied and represented in terms of reggeon exchanges. Unlike the leading gluonic reggeon, related to the BFKL pomeron, the non-leading reggeons are sensitive to the spin and transverse momentum distributions of scattering partons. There are several gluonic reggeons with poles in the vicinity of angular momentum $j=0$ contributing to the perturbative Regge asymptotics of QCD. We extend the high-energy effective action including sub-leading terms which describe these reggeons and their interactions with scattering quarks and gluons in the multi-Regge approximation.Comment: 18 pages, LATEX, 2 EPS figures, revised, to be published in Phys. Lett.