Aspects of BFKL physics at HERA

Abstract

Aspects of small x physics at HERA are discussed in honor of the work of Lev Lipatov, who influenced and motivated a whole generation of physicists to investigate this new region of phase space. The introduction of transverse momentum dependent parton densities is one of the essential aspects of small x and BFKL physics, and its extension to all flavors with application to various processes marks a new milestone.

Contribution to the book "From the past to the future, The legacy of Lev Lipatov" edited by J. Bartels, V. Fadin, E. Levin, A. Levy, V. Kim, A. Sabio-Vera. Citation to xfitter paper added. Typos corrected, thanks to Sel Yuchen Zhou