Dynamics and Hadronization at intermediate transverse momentum at RHIC

TL;DR

This paper discusses how a combined coalescence and fragmentation model explains hadronization phenomena at RHIC, highlighting the role of heavy-light resonances in understanding heavy-quark energy loss and flow in the Quark-Gluon Plasma.

Contribution

It introduces a unified framework incorporating coalescence and fragmentation for both light and heavy quarks, emphasizing the significance of heavy-light resonances in QGP hadronization.

Findings

Coalescence plus fragmentation explains baryon-to-meson ratios and elliptic flow.

Heavy-light resonances are crucial for modeling heavy-quark energy loss and flow.

Resonances provide insight into the microscopic structure of the QGP.

Abstract

The ultra-relativistic heavy-ion program at RHIC has shown that at intermediate transverse momenta ($p_T \simeq 2$-6 GeV) standard (independent) parton fragmentation can neither describe the observed baryon-to-meson ratios nor the empirical scaling of the hadronic elliptic flow ($v_2$) according to the number of valence quarks. Both aspects find instead a natural explanation in a coalescence plus fragmentation approach to hadronization. After a brief review of the main results for light quarks, we focus on heavy quarks showing that a combined fragmentation and quark-coalescence framework is relevant also here. Moreover, within relativistic Langevin simulations we find evidence for the importance of heavy-light resonances in the Quark-Gluon Plasma (QGP) to explain the strong energy loss and collective flow of heavy-quark spectra as inferred from non-photonic electron observables. Such heavy-light resonances can pave the way to a unified understanding of the microscopic structure of the QGP and its subsequent hadronization by coalescence.