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.

Comments: 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