Observation of the collective flow in proton-proton collisions

The scenario of a collective expansion of matter created in proton-proton (p-p) collisions at the CERN Large Hadron Collider (LHC) is discussed. Assuming a small transverse size and a formation time of 0.1fm/c of the source we observe the build up of a substantial transverse flow in relativistic hydrodynamic simulations. In order to demonstrate the collectivity in p-p collisions we propose to look at the multiplicity dependence of the elliptic flow coefficient. If high multiplicity events originate from azimuthally asymmetric events containing two flux tubes, an observable signal above the statistical fluctuations in the measured elliptic flow could appear.