Speaker
Description
The study of event-by-event fluctuations of the mean transverse momentum, $\langle p_{\rm{T} }\rangle$, could probe the nature of the phase transition and seek evidence for temperature fluctuations. In this talk, event-by-event $\langle p_{\rm{T} }\rangle$ and higher order fluctuations of charged particles produced in pp collisions at $\sqrt{s}=5.02$ TeV, Xe--Xe collisions at $\sqrt{s_{\rm{NN}}}=5.44$ TeV, and Pb--Pb collisions at $\sqrt{s_{\rm{NN}}}=5.02$ TeV are reported as a function of charged-particle multiplicity using the ALICE detector at the LHC.
Non-statistical fluctuations are observed in all collision systems, indicating correlated particle emission. The central Pb--Pb collisions show a significant reduction in the fluctuation compared to the peripheral collisions and are in qualitative agreement with previous measurements in Pb--Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV. This effect is discussed in view of radial flow effects and/or the presence of mini-jets. The positive skewness of the $\langle p_{\rm{T} }\rangle$ fluctuation, which has been proposed as an essential consequence of the hydrodynamic evolution of the produced fireball in heavy-ion collisions, is observed. The kurtosis is found to decrease with increasing system size and saturates at the Gaussian expectation for most central Pb--Pb collisions. To investigate the impact of jets in the measurement of the $\langle p_{\rm{T} }\rangle$ fluctuations, a transverse spherocity study was performed and found that jetty events show higher fluctuations compared to isotropic events. The results are compared with widely used Monte Carlo event generators.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | ALICE |
