Quantitative analysis of Geometrical Scaling in Deep Inelastic Scattering

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.