TO: SEMINARIO DI STRINGHE E SUPERGRAVITà:SATURATION IN DEEP INELASTIC SCATTERING FROM ADS/CFT
SESZIONE DI TORINO We analyze interactions at high energies in AdS spaces, at
large and small AdS curvatures. We then use the results to analyze
deep inelastic scattering at small Bjorken x, using the approximate
conformal invariance of QCD at high energies. Hard pomeron exchanges
are resummed eikonally, restoring unitarity at large values of the
phase shift in the dual AdS geometry. At weak coupling this phase is
imaginary, corresponding to a black disk in AdS. In this saturated
regime, cross sections exhibit geometric scaling and have a simple
universal form, which we test against available experimental data
for the proton structure function F_2(x,Q2). We predict, in
particular, the dependence of the cross section on the scaling
variable (Q/Q_s)2 in the deeply saturated region, where Q_s is the
usual saturation scale. We find agreement with current data on F_2
in the kinematical region 0.5 < Q2 < 10 GeV2, x < 10^-2, with an
average 6% accuracy. We conclude by discussing the relation of our
approach with the commonly used dipole formalism.
DATA: 04-11-2008
Istituto Nazionale di Fisica
Nucleare - Piazza dei Caprettari, 70 -
00186 Roma
tel. +39 066840031 - fax +39 0668307924 - email: presidenza@presid.infn.it