Tachyon dynamics of the black disc limit in the hard small x processes in QCD

B. Blok, L. Frankfurt

Research output: Contribution to journalArticlepeer-review


We investigate the effective field theory (EFT) which gives the approximate description of the scattering of the two hard small dipoles in the small x processes in QCD near the black disc limit (BDL). We argue that the perturbative QCD approaches predict the existence of tachyon and visualize it in the approximation where αP = 0. We demonstrate that the high energy behavior of the cross-section depends strongly on the diffusion law in the impact parameter plane. On the other hand, almost threshold behavior of the cross section of the hard processes and multiplicities, i.e. fast increase of cross sections (color inflation), melting of ladders into color network and softening of the longitudinal distributions of hadrons are qualitatively insensitive to the value of diffusion in the impact parameter space. We evaluate αP near the black disk limit and find significant αP as the consequence of the probability conservation.

Original languageEnglish
Pages (from-to)335-345
Number of pages11
JournalNuclear Physics A
Issue number1-4
StatePublished - 1 Feb 2007


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