• Home
  • Evidence for collectivity in pp collisions at the LHC

Evidence for collectivity in pp collisions at the LHC

Measurements of two- and multi-particle angular correlations in pp collisions at √{ s} = 5 , 7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb-1 (5 TeV), 6.2pb-1 (7 TeV), and 0.7pb-1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of KS0 and Λ / Λ ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), KS0 , and Λ / Λ ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT ≈ 2GeV/ c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

Physics Letters B, Volume 765, p. 193 (2017)

File: 
Authors: 
A. Al-bataineh, P. Baringer, A. Bean, S. Boren, J. Bowen, C. Bruner, J. Castle, L. Forthomme, R.P. Kenny III, A. Kropivnitskaya, D. Majumder, W. Mcbrayer, M. Murray, S. Sanders, R. Stringer, J.D. Tapia Takaki, Q. Wang and the CMS Collaboration

Department Communications
Newsletters
Paper of the Week

L. Z. Hadid, M. W. Morooka, J.‐E. Wahlund, L. Moore, T. E. Cravens*, M. M. Hedman, N. J. T. Edberg, E. Vigren, J. H. Waite Jr., R. Perryman, W. S. Kurth, W. M. Farrell, A. I. Eriksson, *KU Author

See previous papers

Mr. Bob T-Shirts: Lab Support