Quantitative analysis of Geometrical Scaling in Deep Inelastic Scattering

TL;DR

This paper investigates geometrical scaling in deep inelastic scattering using HERA data, determining the saturation scale parameter  and confirming the presence of scaling for x<0.2.

Contribution

It provides a quantitative analysis of geometrical scaling and estimates the  parameter for different data binnings, enhancing understanding of saturation effects in DIS.

Findings

 parameter for energy binning: 0.352  0.008

 parameter for Bjorken-x binning: 0.302  0.004

Geometrical scaling is observed for x<0.2

Abstract

We analyze geometrical scaling in deep inelastic scattering using experimental data from HERA ep collider. Parallel analyses are performed for energy and Bjorken-x data binnings. In particular, value of parameter \lambda which governs x-dependence of saturation scale is found for both binnings: \lambda_En = 0.352 \pm 0.008 and \lambda_Bj = 0.302 \pm 0.004. We use the following method: \lambda_En is found as a value for which ratios \sigma^{W1}_{\gamma*p}(\tau)/\sigma^{W2}_{\gamma*p}(\tau) are closest to 1 (\sigma^{Wi}_{\gamma*p} is a photon-proton cross section with definite energy W_i and \tau = Q^2 x^{\lambda} is a scaling variable); \lambda_Bj is found analogously using ratios of cross sections with definite Bjorken-x variable. We show also that GS is present for x<0.2.