Cross sections at HERA

Abstract

The energy dependence of cross sections is discussed as a way to learn about the dynamics of photon induced interactions at HERA. The question of determining the scale of exclusive electroproduction of vector mesons is addressed.

Comments: 17 pages, 17 figures, Talk presented at the 2009 Epiphany meeting, Cracow, Jan 5-7, 2009, dedicated to the memory of Jan Kwiecinski. v2: corrected some figure captions