Does the hard pomeron obey Regge factorisation

Abstract While data for the proton structure function demand the presence of a hard-pomeron contribution even at quite small Q2, previous fits to the pp and p p total cross sections have found that in these there is little or no room for such a contribution. We reanalyse the data and show that it may indeed be present and that, further, it probably obeys Regge factorisation: σ HARD γp (s,Q 1 2 ) σ HARD γp (s,Q 2 2 )=σ HARD pp (s) σ HARD γγ (s,Q 1 2 ,Q 2 2 ) for all values of Q12 and Q22.