Violation of the geometric scaling behavior of the amplitude for running QCD coupling in the saturation region

Bastian Diaz Saez, Eugene Levin

Research output: Contribution to journalArticlepeer-review

Abstract

In this paper we show that the intuitive guess that the geometric scaling behavior should be violated in the case of the running QCD coupling, turns out to be correct. The scattering amplitude of the dipole with the size r depends on new dimensional scale: ΛQCD, even at large values Y=ln(1/x) and l=ln(αS(r2)/αS(1/Qs2)). However, in this region we found a new scaling behavior: the amplitude is a function of ζ=Yl. We state that only in the vicinity of the saturation scale Qss(Qs2)ln(r2Qs2)≤1), the amplitude shows the geometric scaling behavior. Based on these finding the geometric scaling behavior that has been seen experimentally, stems from either we have not probed the proton at HERA and the LHC deeply inside the saturation region or that there exists the mechanism of freezing of the QCD coupling constant at r2≈1/Qs2.

Original languageEnglish
Pages (from-to)83-93
Number of pages11
JournalNuclear Physics A
Volume870-871
Issue number1
DOIs
StatePublished - Nov 2011

Keywords

  • Color glass condensate
  • Geometric scaling behavior
  • Gluon saturation
  • Non-linear evolution

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