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arXiv · 1503.06986

Hadronic "flow" in p--Pb collisions at the Large Hadron Collider?

You Zhou·Xiangrong Zhu·Pengfei Li·Huichao Song
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Abstract

Using the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model, we investigate azimuthal correlations in p--Pb collisions at $\sqrt{s_{_{\rm NN}}}=5.02$ TeV. Comparison with the experimental data shows that UrQMD can not reproduce the multiplicity dependence of 2- and 4-particle cumulants, especially the transition from positive to negative values of $c_{2}\{4\}$ in high multiplicity events, which has been taken as experimental evidence of collectivity in p--Pb collisions. Meanwhile, UrQMD can not qualitatively describe the differential elliptic flow, $v_{2}(p_{\rm T})$, of all charged hadrons at various multiplicity classes. These discrepancies show that the simulated hadronic p--Pb systems can not generate enough collective flow as observed in experiment, the associated hadron emissions are largely influenced by non-flow effects. However, the characteristic $v_{2}(p_{\rm T})$ mass-ordering of pions, kaons and protons is observed in UrQMD, which is the consequence of hadronic interactions and not necessarily associated with strong fluid-like expansions.

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You Zhou, Xiangrong Zhu, Pengfei Li, Huichao Song. 2015-03-24. Hadronic "flow" in p--Pb collisions at the Large Hadron Collider?. https://arxiv.org/abs/1503.06986

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