Measurement of the energy dependence of the total photoproduction cross section with ZEUS at HERA

The energy dependence of the total photoproduction cross section was 
determined from data taken with the ZEUS detector at the ep collider HERA 
with different proton energies. The standard  proton energy of HERA was 920 
GeV. In 2007, HERA also ran with proton energies of 460 GeV and 575 GeV. 
Photoproduction events were selected by identifying electrons scattered at 
low angles in a special tagger.