Do the pp Collisions at LHC Energies Form a Collective Medium?

  • Jajati K. NayakEmail author
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 174)


Whether the relativistic pp collisions at LHC energies serve as the base line for the analysis of heavy ion collisions or they produce a medium like heavy ion collisions is a matter of intense debate. In this work, we analyze the charged hadron spectra produced from pp collisions at \(\sqrt{s_{NN}}=7\) TeV, LHC energy on the basis of hydrodynamical model to address the issue of collectivity and medium formation. The spectra of identified particles (\(\pi , K, p\)) have been evaluated for different mean multiplicities and compared with the data [1] measured by CMS collaboration. It has been found that \(\pi , K\) spectra obtained from high multiplicity events are explained reasonably well for an initial energy density \(\varepsilon _i \ge 1.5\) GeV/fm\(^3\).


Quark Gluon Plasma Charged Hadron Invariant Yield Initial Energy Density Ideal Hydrodynamic 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The author acknowledges P. Ghosh and A. K. Debey for useful discussions.


  1. 1.
    V. Khachatryan et al., CMS collaboration, Eur. Phys. J. C 72, 2164 (2012)Google Scholar
  2. 2.
    A. Bazavov et al., Phys. Rev. D 85, 054503 (2012)CrossRefADSGoogle Scholar
  3. 3.
    S. Borsonyi et al., JHEP 1009, 073 (2010); JHEP 1011, 077 (2010)Google Scholar
  4. 4.
    S. Borsonyi et al., J. Phys. G 38, 124101 (2011)CrossRefADSGoogle Scholar
  5. 5.
    M. Cheng et al., Phys. Rev. D 81, 054504 (2010)CrossRefADSGoogle Scholar
  6. 6.
    S. Gupta, X. Luo, B. Mohanty, H.G. Ritter, N. Xu, Science 332, 1525 (2011)CrossRefADSGoogle Scholar
  7. 7.
    V. Khachatryan et al., CMS collaboration, J. High. Energy. Phys. 09, 091 (2010)Google Scholar
  8. 8.
    K. Aamodt et al., ALICE collaboration, Phys. Rev. D 84, 112004 (2011)Google Scholar
  9. 9.
    L. Van Hove et al., Phys. Lett. B 18, 138 (1982)CrossRefGoogle Scholar
  10. 10.
    Y. Hama, S.S. Padula, Phys. Rev. D 37, 3237 (1988)CrossRefADSGoogle Scholar
  11. 11.
    P. Levai, B. Muller, Phys. Rev. Lett. 67, 1519 (1991)CrossRefADSGoogle Scholar
  12. 12.
    T. Alexopoulos et al., Phys. Lett. B 528, 43 (2002)CrossRefADSGoogle Scholar
  13. 13.
    S.K. Prasad et al., Phys. Rev. C 82, 024909 (2010)CrossRefADSGoogle Scholar
  14. 14.
    J. Casalderry-Solana, U.A. Weidemann, Phys. Rev. Lett. 104, 102301 (2010)CrossRefADSGoogle Scholar
  15. 15.
    D. d’Enterria et al., Eur. Phys. J. C 66, 173 (2010)Google Scholar
  16. 16.
    P. Bozek, Eur. Phys. J. C 71, 1530 (2011)CrossRefADSGoogle Scholar
  17. 17.
    K. Werner, L. Karpenko, T. Pierog, Phys. Rev. Lett. 106, 12204 (2011)CrossRefGoogle Scholar
  18. 18.
    F.M. Liu, K. Werner, Phys. Rev. Lett. 106, 242301 (2011)CrossRefADSGoogle Scholar
  19. 19.
    V. Topor Pop, M. Gyulassy, J. Barrette, C. Gale, A. Warburton, Phys. Rev. C 86, 044902 (2012)Google Scholar
  20. 20.
    M. Csanad, T. Csorgo, arXiv:1307.2082 (2013)
  21. 21.
    P. Ghosh, S. Muhuri, J.K. Nayak, R. Varma, J. Phys. G. 41, 035106 (2014)CrossRefADSGoogle Scholar
  22. 22.
    T. Kalaydzhyan, E. Shuryak, arXiv:1503.05213
  23. 23.
    P. Romatschke, arXiv:1504.02529
  24. 24.
    F. Cooper, G. Frye, Phys. Rev. D. 10, 186 (1974)CrossRefADSGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Variable Energy Cyclotron CentreKolkataIndia

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