---
abstract: 'We show that recently measured transverse momentum spectra of identified particles exhibit geometrical scaling (GS) in scaling variable $\tau_{\tilde{m}_{\rm T}}=(\tilde{m}_{\rm T}/Q_0)^{2} (\tilde{m}_{\rm T}/ W)^{\lambda}$ where $\tilde{m}_{\rm T}=\sqrt{m^2+p^2_{\rm T}}-m$. We explore consequences of GS and show that both mid rapidity multiplicity and mean transverse momenta grow as powers of scattering energy. Furthermore, assuming Tsallis-like parametrization of the spectra we calculate the coefficients of this growth. We also show that Tsallis temperature is related to the average saturation scale.'
address: |
    M. Smoluchowski Institute of Physics, Jagellonian University,\
    Reymonta 4, 30-059 Krakow, Poland
author:
- Michal Praszalowicz
title: Geometrical scaling for identified particles
---

Introduction
============

Geometrical scaling (GS) [@Stasto:2000er] has been observed both in Deep Inelastic Scattering (DIS) at HERA [@GolecBiernat:1998js; @Praszalowicz:2012zh] and in particle production in hadronic collisions [@McLerran:2010ex; @Praszalowicz:2011tc; @Praszalowicz:2011rm]. It is an immediate consequence of the existence of an intermediate energy scale called saturation scale, denoted hereafter as $Q_{\mathrm{s}}$. Saturation [@sat1; @sat2] (for a review see [@Mueller:2001fv; @McLerran:2010ub]) appears due to the nonlinearities of parton evolution at small Bjorken $x$. General form of this evolution is given by the so-called JIMWLK equations [@jimwlk] which in the large $N_{\mathrm{c}}$ limit reduce to the Balitsky-Kovchegov equation [@BK]. These 