Improved Geometrical Scaling at the LHC

Abstract

We show that geometrical scaling exhibited by the $p_{\mathrm{T}}$ spectra measured by the CMS collaboration at the LHC is substantially improved if the exponent $\lambda$ of the saturation scale depends on $p_{\mathrm{T}}$. This dependence is shown to be the same as the dependence of small $x$ exponent of $F_2$ structure function in deep inelastic scattering taken at the scale $Q=p_{\mathrm{T}}/2$

Comments: 4 pages, 3 figures. In v2 a misprint concerning p_T dependence of lambda_eff corrected. In v3: small corrections, reference added, to appear in Physical Review Letters