Production of two gluons in the Lipatov effective action formalism

Abstract

The one-loop diffractive amplitude for emission of two real gluons with widely different rapidities is studied in the Lipatov effective action formalism. It is shown that after integration over longitudinal momenta in the loop the resulting expression coincides with the one obtained by the Lipatov-Bartels formalism in transversal space provided the same prescription is used to exclude divergent contributions as previously proposed for emission of a single real gluon.

One-loop light-cone QCD, effective action for reggeized gluons and QCD RFT calculus

“…(80) in the framework of the approach. Although this propagator is well known and widely used in all applications of the effective action, see [9][10][11][12][13][14][15][16][17][18][19][20][21][22] and [33][34][35][36][37][38], the full computation of the propagator in the framework of interest was done for the first time. We can consider this calculation as a check of the selfconsistency of the approach and also as an explanation of the methods of the calculation of small-x BFKL-based vertices in the framework.…”

“…The action for the interaction of reggeized gluons was introduced in the series of papers [1][2][3][4][5][6] and describes multi-Regge processes at high energies; see [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. There are the following important applications of this action: it can be used for the calculation of production amplitudes in different scattering processes and calculation of sub-leading, unitarizing corrections to the amplitudes and production vertices; see [1][2][3][4][5][6].…”

High energy QCD Lipatov’s effective action in Euclidean space

“…This functional effectively determines the vertices of interactions of A ± fields with the instanton fields in the framework of high energy Euclidean QCD RFT, after the inverse continuation to Minkowski space it will determine the vertices of interactions of Reggeon with instanton fields as well. We note, that using the diagrammatic approach of [3][4][5][6][7][14][15][16][17][18][19][20][21][22][23][24][25][26][27], the effective currents determine the Feynman rules for the construction of the vertices of interaction of gluons with instanton and Reggeon fields. Namely, instead the Eq.…”

Effective action for reggeized gluons, classical gluon field of relativistic color charge and color glass condensate approach

“…The effective action approach of [2][3][4][5][6][7] can be considered as some generalization of Gribov's Regge calculus, [1], for the case of QCD degrees of freedom. Besides the usual gluon field, it includes two additional reggeon fields and widely used for the calculations of different quasi-elastic LO and NLO production amplitudes in the multi-Regge kinematics, see [51][52][53][54][55][56][57][58][59][60], or calculation of NLO corrections to the BKP, [61,62], kernel, see [63].…”