https://doi.org/10.1140/epjc/s10052-010-1530-0
Elliptic flow in proton–proton collisions at √s = 7 TeV
1
The H. Niewodniczański Institute of Nuclear Physics, 31342, Kraków, Poland
2
Institute of Physics, Rzeszów University, 35959, Rzeszów,
Poland
Received:
27
October
2010
Revised:
17
November
2010
Published online:
5
January
2011
The angular correlations measured in proton–proton collisions at 
TeV are decomposed into contributions from back to back emission and elliptic flow. Modeling the dominant term in the correlation functions as a momentum conservation effect or as an effect of the initial transverse velocity of the source, the remaining elliptic flow component can be estimated. The elliptic flow coefficient extracted from the CMS Collaboration data is 0.06–0.01. Part of the extracted elliptic flow is due to non-flow effects. The minimal elliptic flow necessary to explain the observed ridge structure in the data is 0.04–0.06, depending on the transverse momentum bin. This number could serve as an estimate of the amount of collective flow in proton–proton collisions, if it is assumed to be generated during the expansion of the dense fireball. No additional small-angle, ridge-like correlations are needed to explain the experimental data.
© Springer-Verlag / Società Italiana di Fisica, 2011
