Saturation and Geometrical Scaling in Small Systems

M Praszalowicz

doi:10.5506/aphyspolbsupp.9.395

Abstract

Saturation and geometrical scaling (GS) of gluon distributions are a consequence of the non-linear evolution equations of QCD. We argue that in pp GS holds for the inelastic cross-section rather than for the multiplicity distributions. We also discuss possible fluctuations of the proton saturation scale in pA collisions at the LHC.

Highlights

Saturation and geometrical scaling (GS) of gluon distributions are a consequence of the non-linear evolution equations of QCD
In Eq (1), we have assumed that produced gluons are in the mid-rapidity region (y 0), both Bjorken xs of colliding glouns are equal to x1 x2
Repeating the procedure of constructing the ratios of the multiplicities rather than of the cross sections, we find the best scaling for λ = 0.22 ÷ 0.24 [7]

Summary

Introduction

Saturation and geometrical scaling (GS) of gluon distributions are a consequence of the non-linear evolution equations of QCD. In the case of DIS, S⊥ = σ0 is the dipole–proton cross section for large dipoles and in (2), S⊥ is the transverse size of an overlap of two large nuclei for a given centrality class. We see that three different curves from the left panel in Fig. 1 overlap over some region if plotted in terms of the scaling variable τ .

Results

Conclusion