DOI 10.1007/s100520000351
Conformal couplings and "azimuthal matching''
of QCD
pomerons
N. Marchal** Stagiaire de Diplôme d'Etudes Approfondies de Physique Théorique (ENS, Paris). - R. Peschanski
Service de Physique Théorique CEA-Saclay, 91191
Gif-sur-Yvette Cedex, France
Received: 25 October 1999 / Revised version: 19 January 2000 /
Published online: 14 April 2000 - © Springer-Verlag 2000
Abstract
Using the asymptotic conformal invariance of perturbative QCD
we derive the
expression
of the coupling of external states to all conformal spin pcomponents of the
forward
elastic amplitude. Using the wave function formalism for structure
functions at
small
x, we derive the perturbative coupling of the virtual photon
for p= 1,
which is
maximal for linear transverse polarization. The non-perturbative
coupling to
the
proton is discussed in terms of "azimuthal matching'' between
the proton color
dipoles and
the 
configurations of the photon. As an application,
the recent
conjecture of
a second QCD pomeron related to the conformal spin-1 component
is shown to rely
upon a
strong azimuthal matching of the p= 1 component
in 
-proton scattering.
Copyright Società Italiana di Fisica, Springer-Verlag 2000
