Exclusive diffraction and Pomeron trajectory in ep collisions
  The exclusive diffractive production of vector mesons and real photons in ep collisions has been studied at HERA in a wide kinematic range. Here we present the most recent experimental results together with a Regge-type model. We deduce the Pomeranchuk trajectory (Pomeron) by analyzing the HERA data on deeply virtual Compton scattering (DVCS), and then discuss its basic properties, namely its apparent "hardness" and its "non-flat" behavior, different from the claims of some authors. 
S. Fazio