Effect of radial flow on two particle correlations with identified triggers at intermediate $p_{T}$ in p-Pb collisions at $\sqrt{s_{NN}} = $ 5.02 TeV

TL;DR

This study investigates how radial flow influences two-particle correlations with identified triggers in p-Pb collisions at 5.02 TeV, revealing different multiplicity dependencies for pions and protons, and suggesting hydrodynamic effects in small systems.

Contribution

It provides the first detailed analysis of identified particle-triggered correlations in p-Pb collisions using a hybrid hydrodynamic model, highlighting the role of radial flow.

Findings

Pion-triggered yields show negligible multiplicity dependence.

Proton-triggered yields decrease with increasing multiplicity.

Hydrodynamic evolution may cause suppression of proton correlations.

Abstract

Results from the two-particle correlation between identified triggers (pions ($\pi^{\pm}$) , protons (p/$\bar{p}$))) and un-identified charged particles at intermediate transverse momentum ($p_{T}$) in p-Pb collisions at $\sqrt{s_{NN}} = $ 5.02 TeV have been presented. The events generated from a hybrid Monte-Carlo event generator, EPOS 3.107 that implements a flux-tube initial conditions followed by event by event 3+1D viscous hydrodynamical evolution, have been analysed to calculate two-dimensional correlation functions in $\Delta\eta$-$\Delta\phi$. The strength of angular correlations at small relative angles (jet-like correlations), quantified in terms of near-side jet-like per-trigger yield has been calculated as a function of the event multiplicity. The yield associated with pion triggers exhibit negligible multiplicity dependence, while the proton-triggered yield shows a gradual suppression from low to high multiplicity events. In small collision systems like p-Pb where jet modification is expected to be less dominant, the observed suppression may be associated with the hydrodynamical evolution of the bulk system that generates an outward radial flow. Analogous measurements in Au-Au collisions at RHIC energy have shown a hint of dilution in proton-triggered correlation at its highest multiplicity suggesting that the soft physics processes in p-Pb and heavy ion collisions may have qualitative similarity.