Quantitative Study of Geometrical Scaling in Deep Inelastic Scattering at HERA

Abstract

We propose a method to assess the quality of geometrical scaling in Deep Inelastic Scattering and apply it to the combined HERA data on ${\gamma }^{\ast }p$ cross-section. Using two different approaches based on Bjorken $x$ binning and binning in ${\gamma }^{\ast }p$ scattering energy $W$, we show that geometrical scaling in variable $\tau \sim Q^2{x}^{\lambda }$ works well up to Bjorken $x$'s 0.1. The corresponding value of exponent $\lambda$ is 0.32 -- 0.34.

Comments: 18 pages, 11 figures, version accepted in JHEP, new discussion of experimental errors