Speaker
Description
Two-particle angular correlation measurements are sensitive probes of the interactions of the medium formed in heavy-ion collisions and the particles propagating through it. Such measurements are done by determining the distribution of the relative pseudorapidity ($\Delta\eta$) and azimuthal angle ($\Delta\varphi$) of particles with respect to a higher $p_{\rm T}$ trigger particle ($1 < p_{\rm T,trig} < 8~\text{GeV}/c$). The near-side peak is fitted, accounting for $\Delta\eta$-independent long-range correlations, and the centrality evolution of the width (variance) of the fitted distribution is investigated. In Pb-Pb collisions a significant broadening of the near-side peak in the $\Delta\eta$ direction is observed from peripheral to central collisions, while in the $\Delta\varphi$ direction the peak is almost independent of centrality. For the 10% most central events, a departure from the Gaussian shape is also observed at low transverse momentum ($1 < p_{\rm T,assoc} < 2~\text{GeV}/c$, $1 < p_{\rm T,trig} < 3~\text{GeV}/c$). In this contribution the results obtained by the ALICE experiment in Pb-Pb and pp collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV will be shown, and they will be interpreted in terms of radial and elliptic flow by comparing them to AMPT model simulations.
| Presentation type | Oral |
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