Eur. Phys. J. C 70, 983-998 (2010)
https://doi.org/10.1140/epjc/s10052-010-1500-6

Using HERA data to determine the infrared behaviour of the BFKL amplitude

¹ Deutsches Elektronen-Synchrotron DESY, 22607, Hamburg, Germany
² Petersburg Nuclear Physics Institute, Gatchina 188300, St. Petersburg, Russia
³ II. Institut für Theoretische Physik, Universität Hamburg, 22761, Hamburg, Germany
⁴ School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
⁵ Theory Group, Physics Department, CERN, 1211, Geneva 23, Switzerland

Graeme.Watt@cern.ch

Received: 10 May 2010
Revised: 1 October 2010
Published online: 18 November 2010

Abstract

We determine the infrared behaviour of the BFKL forward amplitude for gluon–gluon scattering. Our approach, based on the discrete pomeron solution, leads to an excellent description of the new combined inclusive HERA data at low values of x (<0.01) and at the same time determines the unintegrated gluon density inside the proton, for squared transverse momenta of the gluon less than 100 GeV². The phases of this amplitude are sensitive to the non-perturbative gluonic dynamics and could be sensitive to the presence of Beyond-the-Standard-Model particles at very high energies.