Quark-antiquark contribution to the BFKL kernel

The quark-antiquark contribution to the BFKL kernel is calculated. Using the effective vertex for the $q\bar q$ pair production in the Reggeon-Reggeon collision we find this contribution by integrating the square of this vertex over relative transverse momenta and fractions of longitudinal momenta of produced particles.Comment: 12 pages, Late

Gribov's Theorem on Soft Emission and the Reggeon-Reggeon-Gluon Vertex at Small Transverse Momentum

In spite of the fact that the Gribov's theorem about the region of applicability of the soft emission factorization cannot be referred literally to the case of massless charged particles, it can be used for the calculation of soft emission amplitudes in such a case also. We demonstrate this for the gluon production amplitude in the multi-Regge kinematics with small transverse momentum.Comment: 9 pages, Late

NLO inclusive jet production in kTk_T--factorization

The inclusive production of jets in the central region of rapidity is studied in $k_T$-factorization at next-to-leading order (NLO) in QCD perturbation theory. Calculations are performed in the Regge limit making use of the NLO BFKL results. A jet cone definition is introduced and a proper phase--space separation into multi-Regge and quasi-multi-Regge kinematic regions is carried out. Two situations are discussed: scattering of highly virtual photons, which requires a symmetric energy scale to separate the impact factors from the gluon Green's function, and hadron-hadron collisions, where a non--symmetric scale choice is needed.Comment: 36 pages, 5 figures. Version to be published in JHEP. Some typos correcte

The impact factor for the virtual photon to light vector meson transition

We evaluate in the next-to-leading approximation the forward impact factor for the virtual photon to light vector meson transition in the case of longitudinal polarization. We find that in the hard kinematic domain, both in the leading and in the next-to-leading approximation, the expression for the impact factor factorizes, up to power suppressed corrections, into the convolution of a perturbatively calculable hard-scattering amplitude and a meson twist-2 distribution amplitude.Comment: 31 pages latex; few comments and one reference added; version to appear in Eur. Phys. Journal

Photon-Reggeon Interaction Vertices in the Nla

We calculate the effective vertices for the quark-antiquark and the quark-antiquark-gluon production in the virtual photon - Reggeized gluon interaction. The last vertex is considered at the Born level; for the first one the one-loop corrections are obtained. These vertices have a number of applications; in particular, they are necessary for calculation of the virtual photon impact factor in the next-to-leading logarithmic approximation.Comment: 20 pages, references adde

The Gluon Impact Factors

We calculate in the next-to-leading approximation the non-forward gluon impact factors for arbitrary color state in the $t$-channel. In the case of the octet state we check the so-called "second bootstrap condition" for the gluon Reggeization in QCD, using the integral representation for the impact factors. The condition is fulfilled in the general case of an arbitrary space-time dimension and massive quark flavors for both helicity conserving and non-conserving parts.Comment: 32 pages, LaTeX, 1 EPS figure, uses epsf.sty and axodraw.st

The Quark Impact Factors

We calculate in the next-to-leading approximation the non-forward quark impact factors for both singlet and octet color representation in the $t$-channel. The integral representation of the octet impact factor in the general case of arbitrary space-time dimension and massive quark flavors is used to check the so-called "second bootstrap condition" for the gluon Reggeization at the next-to-leading logarithmic approximation in perturbative QCD. We find that it is satisfied for both helicity conserving and non-conserving parts. The integrations are then performed for the explicit calculation of the impact factors in the massless quark case.Comment: 23 pages, LaTeX, 1 EPS figure, uses epsf.sty and axodraw.st