Three-Reggeon cuts in QCD amplitudes

V.S Fadin,D Melikhov,I Volobuev

doi:10.1051/epjconf/201922203006

V.S Fadin, D Melikhov + Show 1 more

Open Access

https://doi.org/10.1051/epjconf/201922203006

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Abstract

One of remarkable properties of QCD is the gluon Reggeization. The Reggeized gluon is the primary Reggeon in QCD; Pomeron and Odderon appear as compound states of the Reggeized gluons. Due to negative signature the Reggeized gluon gives the main contributions to high energy QCD amplitudes in each order ofperturbation theory. In the leading and next-to-leading logarithmic approximations these amplitudes aregiven by the Regge pole contributions. In the next-to-next-to-leading approximation the pole form of the amplitudes is violated by contributions of three-Reggeon cuts. We discuss these contributions to elastic QCD amplitudes.

Highlights

One of remarkable properties of QCD is the Reggeization of all elementary particles in perturbation theory, which is very important for theoretical description of high energy processes.The gluon Reggeization is especially important because it determines the high energy behaviour of non-decreasing with energy cross sections
The BFKL equation was derived assuming the pole Regge form of amplitudes with gluon quantum numbers in cross channels and negative signature. It is proved in all orders of perturbation theory that this form is valid both in the leading and in the next-to-leading logarithmic approximations. This form is violated in the NNLLA
The breaking the pole Regge form should have been expected, because it is well known that Regge poles in the complex angular momenta plane generate Regge cuts

Summary

Introduction

One of remarkable properties of QCD is the Reggeization of all elementary particles in perturbation theory, which is very important for theoretical description of high energy processes. The gluon Reggeization is especially important because it determines the high energy behaviour of non-decreasing with energy cross sections. It appears to be the basis of the BFKL (Balitskii-Fadin-Kuraev-Lipatov) equation, which was first derived in nonAbelian theories with spontaneously broken symmetry [1,2,3] and whose applicability in QCD was shown [4]. Using the infrared factorization techniques, consideration of the terms responsible for breaking of the pole Regge form in amplitudes of elastic scattering in QCD was performed by [9]-[11]. We discuss here the cut contributions up to four loops

Two loops

Three loops

Four loops

Summary