Eur. Phys. J. C (2007) 51: 103-111
https://doi.org/10.1140/epjc/s10052-007-0270-2

Regular Article - Theoretical Physics

The reggeon→2reggeons+particle vertex in the Lipatov effective action formalism

Department of High Energy Physics, University of S.Petersburg, 198904, St. Petersburg, Russia

^* e-mail: ovsky@pobox.spbu.ru

Received: 22 December 2006
Revised: 17 February 2007
Published online: 1 June 2007

Abstract

The vertex for gluon emission during the splitting of a reggeized gluon into two is constructed in the framework of the Lipatov effective action formalism. Its reduction to a pure transverse form for the diffractive amplitude gives the standard Bartels vertex plus an additional contribution, corresponding to the emission from a pointlike splitting vertex. This additional contribution turns out to be given by a longitudinal integral divergent both in the ultraviolet and infrared. A certain specific recipe for this part, including the principal value prescription for the integration, allows one to eliminate this unwanted contribution.