25 research outputs found
Gluon emission at small longitudinal momenta in the QCD effective action approach
In the framework of the QCD effective action the vertices of gluon emission
in interaction of reggeons are studied in the limit of small longitudinal
momenta of the emitted gluon. It is found that the vertices drastically
simplify in this limit so that the gluon becomes emitted from a single reggeon
coupled to the projectile and target via multireggeon vertices. Contribution
from this kinematical region is studied for double and 2x2 elementary
collisions inside the composite projectile and target.Comment: 20 pages, 13 figures; to be published in Eur.Phys.Jour.
Diffractive scattering on the deuteron projectile in the NLO: triple interaction of reggeized gluons
High-mass diffractive production of protons on the deuteron target is studied
in the next-to-leading order (NLO) of the perturbative QCD in the BFKL
approach. The non-trivial part of the NLO contributions coming from the triple
interactions of the exchanged reggeons is considered. Analytic formulas are
presented and shown to be infrared free and so ready for practical calculation.Comment: 28 pages, 2 figures; to be published in Eur.Phys.Jour.
Origin of the second coherent peak in the dynamical structure factor of an asymmetric spin-ladder
Appearance of the second coherent peak in the dynamical structure factor of
an asymmetric spin ladder is suggested. The general arguments are confirmed by
the first order (with respect to the asymmetry) calculation for a spin ladder
with singlet-rung ground state. Basing on this result a new interpretation is
proposed for the inelastic neutron scattering data in the spin gap compound
CuHpCl.Comment: 11 page
Gluon production on two centers and the effective action approach
Application of the effective action formalism is studied for processes in
which the reggeons may split. It is shown that the gluon production on two
centers is described by the contribution of the
Reggeon-to-two-Reggeons-plus-Particle vertex supplemented by certain singular
contributions from the double gluon exchange. The rules for longitudinal
integrations are established from the comparison to perturbative QCD amplitude.
Convenient expressions for application to the inclusive gluon production are
derived.Comment: 15 pages, 7 figures; some misprints corrected; submitted to
Eur.Phys.Jour.
On the application of the effective action approach to amplitudes with reggeon splitting
Application of the effective action approach to amplitudes with loop
integration is studied for collisions on two and three centers with possible
gluon emission. A rule is formulated for the integration around pole
singularities in the induced vertices which brings the results in agreement
with the QCD. It is demonstrated that the amplitudes can be restored from the
purely transverse picture by introducing the standard Feynman propagators for
intermediate gluons and quarks.Comment: 16 pages, 9 figures; submitted to Eur.Phys.Jour.
Local one-dimensional reggeon model of the interaction of pomerons and odderons
We propose the one-dimensional reggeon theory describing local pomerons and
odderons. It generalizes the well-known one-dimensional theory of pomerons (the
Gribov model) and includes only triple interaction vertices. The proposed
theory is studied by numerical methods: the one-particle pomeron and odderon
propagators and the pA amplitude are found as functions of rapidity by
integrating the evolution equation.Comment: 19 pages, 11 figures; submitted to Eur.Phys.Jour.
Production of a gluon with the exchange of three reggeized gluons in the Lipatov effective action approach
In the Regge kinematics the amplitude for gluon production off three
scattering centers is found in the Lipatov effective action technique. The
vertex for gluon emission with the reggeon splitting in three reggeons is
calculated and its transversality is demonstrated. It is shown that in the sum
of all contributions terms containing principal value singularities are
cancelled and substituted by the standard Feynman poles. These results may be
used for calculation of the inclusive cross-section for gluon production on two
nucleons in the nucleus.Comment: 22 pages, 9 figures; submitted to Eur.Phys.Jour.
On the inclusive gluon production in the Lipatov effective action formalism
The process of gluon production in quark-nucleus collisions is studied in the
framework of Lipatov's effective action formalism. The relevant simplifications
and rules for longitudinal integrations are discussed in detail. The results
obtained with the help of these rules correspond to the purely transversal
formalism based on effective vertices in the transversal space.Comment: 15 pages, 7 figures; some references added; to be published in
Eur.Phys.Jour.