The SAGEX review on scattering amplitudes Chapter 15: The multi-Regge limit

Abstract

We review the Regge and multi-Regge limit of scattering amplitudes in gauge theory, focusing on QCD and its maximally supersymmetric cousin, planar ${\cal N}=4$ super-Yang-Mills theory. We identify the large logarithms that are developed in these limits, and the progress that has been made in resumming them, towards next-to-next-to-leading logarithms for BFKL evolution in QCD, as well as all-orders proposals in planar ${\cal N}=4$ super-Yang-Mills theory and the perturbative checks of those proposals. We also cover the application of single-valued multiple polylogarithms to this important kinematical limit of particle scattering.

The SAGEX review on scattering amplitudes*

“…2.15. The multi-Regge limit [15] At high-energy hadron colliders, jets of hadrons are produced copiously, emerging from underlying collisions of quarks and gluons, which can have high multiplicity due to the nonabelian nature of QCD. Multi-jet production extends over large ranges in rapidity (roughly the logarithm of the polar angle), and is further enhanced logarithmically in such Regge limits and multi-Regge kinematics.…”

The SAGEX review on scattering amplitudes Chapter 5: Analytic bootstraps for scattering amplitudes and beyond

“…Last but not least, an excellent source of boundary kinematic data for the bootstrap is offered by the high energy or multi-Regge kinematics (MRKs), a very rich subject in its own right, which will be the focus of chapter 15 [170] of this review [42]. This owes to the development of an effective description of the latter by Balitsky, Fadin, Lipatov and Kuraev originally in QCD, that was later extended also to planar N = 4 SYM [12,25,163,[171][172][173][174][175][176][177].…”