Regge models of the proton structure function with and without hard Pomeron: a comparative analysis

A comparative phenomenological analysis of Regge models with and without a hard Pomeron component is performed using a common set of recently updated data. It is shown that the data at small $x$ do not indicate explicitly the presence of the hard Pomeron. Moreover, the models with two soft-Pomeron components (simple and double poles in the angular momentum plane) with trajectories having intercept equal one lead to the best description of the data not only at $W>3$ GeV and at small $x$ but also at all $x\leq 0.75$ and $Q^{2}\leq 30000$ GeV$^{2}$.