Saturation and BFKL dynamics in the HERA data at small-x

By E. Iancu, K. Itakura, S. Munier. 2003

360 citations recorded by the source corpus.

Abstract We show that the HERA data for the inclusive structure function F2(x,Q2) for x⩽10−2 and 0.045⩽Q2⩽45 GeV2 can be well described within the color dipole picture, with a simple analytic expression for the dipole–proton scattering amplitude, which is an approximate solution to the non-linear evolution equations in QCD. For dipole sizes less than the inverse saturation momentum 1/Qs(x), the scattering amplitude is the solution to the BFKL equation in the vicinity of the saturation line. It exhibits geometric scaling and scaling violations by the diffusion term. For dipole sizes larger than 1/Qs(x), the scattering amplitude saturates to one. The fit involves three parameters: the proton radius R, the value x0 of x at which the saturation scale Qs equals 1 GeV, and the logarithmic derivative of the saturation momentum λ. The value of λ extracted from the fit turns out to be consistent with a recent calculation using the next-to-leading order BFKL formalism.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/816fb36a5a3bb90295c32fe2dc9bd4269c503589

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In Nuclear and High Energy Physics

Citations in the corpus

Collinearly-improved BK evolution meets the HERA data (2015, background): “For instance, the ‘IIM’ fit in [20] attempted to capture some general features of the non-linear evolution, like geometric scaling with an anomalous dimension and the BFKL diffusion, that were expected to hold beyond leading order [9,29].”
Solving The High Energy Evolution Equation Including Running Coupling Corrections (2007, methodology): “For example, the inclusive structure function measured in HERA is fitted in [54,56] within the region 0.”
Deep inelastic scattering at strong coupling from gauge/string duality: the saturation line (2007, background): “ter taking into account the next–to–leading order BFKL corrections [2, 3], this value is reduced to vs ≈ 0.3 [31], which is indeed in the ballpark of the various phenomenological analyses (see, e.g., [34, 35, 36] for studies at HERA). We now return to the problem of dipole–onium scattering, cf. Eqs.”
Nonlinear QCD meets data: A global analysis of lepton-proton scattering with running coupling Balitsky-Kovchegov evolution (2009, background): “Very succinctly, some of these works [29] incorporated features of BFKL dynamics and explicit impact parameter dependence in the scattering amplitude [30,32,33], whereas [39] focused in including DGLAP evolution into the model, which resulted in a improved fit to the higher Q(2) data.”
Heavy-flavour and quarkonium production in the LHC era: from proton–proton to heavy-ion collisions (2015, methodology): “LM use two different models for N(r, x): the IIM model [815] which is a parametrisation of the expected behaviour of the solution to the BK equation [816–818] which includes a nonlinear term for the evolution of N(r, x); and the IPsat model [812, 819] which uses DGLAP equations to evolve an eikonali”
A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector (2012, methodology): “The latter include calculations based on solutions of the running coupling Balitsky-Kovchegov equation [348] and other more phenomenological models of the dipole amplitude without [261], or with [277] impact parameter dependence.”