Acknowledgements We would like to thank  Jan Nemchik ,  William A. Horowitz ,  Ivan Vitev , and  Klaus Werner  for providing the model calculations shown in this paper. This work was supported by the grants  RFBR 10-02-91052  and  RFBR 12-02-91527. The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the  Worldwide LHC Computing Grid  (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector:  State Committee of Science, World Federation of Scientists (WFS)  and  Swiss Fonds Kidagan ,  Armenia ,  Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ,  Financiadora de Estudos e Projetos (FINEP) ,  Fundacão de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ;  National Natural Science Foundation of China (NSFC) , the  Chinese Ministry of Education (CMOE)  and the  Ministry of Science and Technology of China (MSTC) ;  Ministry of Education and Youth of the Czech Republic ;  Danish Natural Science Research Council , the  Carlsberg Foundation  and the  Danish National Research Foundation ; The  European Research Council  under the European Community's  Seventh Framework Programme ;  Helsinki Institute of Physics  and the  Academy of Finland ;  French CNRS-IN2P3 , the  'Region Pays de Loire', 'Region Alsace', 'Region Auvergne'  and  CEA, France ;  German BMBF  and the  Helmholtz Association ;  General Secretariat for Research and Technology, Ministry of Development, Greece ;  Hungarian OTKA  and  National Office for Research and Technology (NKTH) ;  Department of Atomic Energy and Department of Science and Technology of the Government of India ;  Istituto Nazionale di Fisica Nucleare (INFN)  and  Centro Fermi -Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Italy ;  MEXT   Grant-in-Aid for Specially Promoted Research, Japan ;  Joint Institute for Nuclear Research, Dubna ;  National Research Foundation of Korea (NRF) ;  CONACYT, DGAPA, México, ALFA-EC  and the  EPLANET Program  ( European Particle Physics Latin American Network) Stichting voor Fundamenteel Onderzoek der Materie (FOM)  and the  Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) ,  Netherlands ;  Research Council of Norway (NFR) ;  Polish Ministry of Science and Higher Education ;  National Science Centre, Poland ;  Ministry of National Education/Institute for Atomic Physics  and  CNCS-UEFISCDI -Romania ;  Ministry of Education and Science of Russian Federation, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal Agency for Science and Innovations and The Russian Foundation for Basic Research; Ministry of Education of Slovakia ;  Department of Science and Technology, South Africa ;  CIEMAT ,  EELA, Ministerio de Economía y Competitividad (MINECO) of Spain, Xunta de Galicia  ( Consellería de Educación ),  CEADEN, Cubaenergía, Cuba , and  IAEA (International Atomic Energy Agency );  Swedish Research Council (VR)  and  Knut & Alice Wallenberg Foundation (KAW) ;  Ukraine Ministry of Education and Science; United Kingdom Science and Technology Facilities Council (STFC) ; The  United States Department of Energy , the  United States National Science Foundation , the  State of Texas , and the  State of Ohio.