Event-by-event mean $p_{\rm T}$ fluctuations in pp and Pb-Pb collisions at the LHC

Understand

Event-by-event fluctuations of the mean transverse momentum of charged particles produced in pp collisions at $\sqrt{s}$ = 0.9, 2.76 and 7 TeV, and Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV are studied as a function of the charged-particle multiplicity using the ALICE detector at the LHC.

• Dynamical fluctuations indicative of correlated particle emission are observed in all systems.
• The results in pp collisions show little dependence on collision energy.
• The Monte Carlo event generators PYTHIA and PHOJET are in qualitative agreement with the data.