217590
20181203024210.0
1029-8479
10.1007/Jhep03(2010)133
doi
ARTICLE
Deep inelastic scattering in conformal QCD
New York
2010
Springer
2010
65
Journal Articles
We consider the Regge limit of a CFT correlation function of two vector and two scalar operators, as appropriate to study small-x deep inelastic scattering in N = 4 SYM or in QCD assuming approximate conformal symmetry. After clarifying the nature of the Regge limit for a CFT correlator, we use its conformal partial wave expansion to obtain an impact parameter representation encoding the exchange of a spin j Reggeon for any value of the coupling constant. The CFT impact parameter space is the three-dimensional hyperbolic space H-3, which is the impact parameter space for high energy scattering in the dual AdS space. We determine the small-x structure functions associated to the exchange of a Reggeon. We discuss unitarization from the point of view of scattering in AdS and comment on the validity of the eikonal approximation. We then focus on the weak coupling limit of the theory where the amplitude is dominated by the exchange of the BFKL pomeron. Conformal invariance fixes the form of the vector impact factor and its decomposition in transverse spin 0 and spin 2 components. Our formalism reproduces exactly the general results predict by the Regge theory, both for a scalar target and for gamma* - gamma* scattering. We compute current impact factors for the specific examples of N = 4 SYM and QCD, obtaining very simple results. In the case of the R-current of N = 4 SYM, we show that the transverse spin 2 component vanishes. We conjecture that the impact factors of all chiral primary operators of N = 4 SYM only have components with 0 transverse spin.
Deep Inelastic Scattering
AdS-CFT Correspondence
Cornalba, Lorenzo
Ctr Studi & Ric E Fermi, I-00184 Rome, Italy
Costa, Miguel S.
Univ Porto, Fac Ciencias, Dept Fis, P-4169007 Oporto, Portugal
Penedones, João Miguel
266889
249789
133
3
Journal Of High Energy Physics
FSL
252561
U13203
oai:infoscience.tind.io:217590
article
SB
253580
EPFL-ARTICLE-217590
OTHER
PUBLISHED
REVIEWED
ARTICLE