Two aspects of the Regge limit in QCD: Double Logs in Exclusive observables and Infrared Effects in Cross Sections

Abstract

Two relevant points related to the application of the BFKL formalism to phenomenology are discussed. First, we have presented a set of observables characterizing multi-jet configurations event by event (average transverse momentum, average azimuthal angle, average ratio of jet rapidities) which can be used to find distinct signals of BFKL dynamics at the LHC. A numerical analysis has been shown using the Monte Carlo event generator BFKLex, modified to include higher-order collinear corrections in addition to the transverse-momentum implementation of the NLO kernel. We require to have two tagged forward/backward jets in the final state. Second, the structure of the BFKL equation changes if infrared boundary conditions are imposed when considering the running of the coupling. The cut in the complex angular momentum plane becomes an infinite series of Regge poles. Integrating along a contour off the real axis we find a strong dependence of the intercepts and collinear regions on the choice of the boundary conditions. The mean transverse scales dominant in the gluon ladder increase. This could have interesting phenomenological consequences.Comment: 6 pages, presented by A. Sabio Vera at the 25th International Workshop on Deep Inelastic Scattering and Related Topics, 3-7 April 2017, Birmingham, U