QCD, conformal invariance and the two Pomerons
S. Munier - R. Peschanski
CEA, Service de Physique Theorique, CE-Saclay, F-91191 Gif-sur-Yvette Cedex, France
Received: 8 February 1999 / Revised version: 8 March 1999 / Published online: 18 June 1999
Using the solution of the BFKL equation including the leading and subleading conformal spin components, we show how the conformal invariance underlying the leading expansion of perturbative QCD leads to elastic amplitudes described by two effective Pomeron singularities. One Pomeron is the well-known "hard'' BFKL leading singularity, while the new one appears from a shift of the higher conformal spin BFKL singularities from subleading to leading position. This new effective singularity is compatible with the "soft'' Pomeron and thus, together with the "hard'' Pomeron, meets at large Q2 the "double Pomeron'' solution which has recently been conjectured by Donnachie and Landshoff.