42 research outputs found
Does quark-gluon plasma feature an extended hydrodynamic regime?
We investigate the response of the near-equilibrium quark-gluon plasma (QGP)
to perturbation at non-hydrodynamic gradients. We propose a conceivable
scenario under which sound mode continues to dominate the medium response in
this regime. Such a scenario has been observed experimentally for various
liquids and liquid metals. We further show this extended hydrodynamic regime
(EHR) indeed exists for both the weakly-coupled kinetic equation in the
relaxation time approximation (RTA) and the strongly-coupled
supersymmetric Yang-Mills (SYM) theory. We construct a simple but nontrivial
extension of M{\"u}eller-Isareal-Stewart (MIS) theory, namely MIS*, and
demonstrate that it describes EHR response for both RTA and SYM theory. This
indicates that MIS* equations can potentially be employed to search for QGP EHR
via heavy-ion collisions.Comment: 9 pages, 4 figure
Initial-state and final-state effects on hadron production in small collision systems
Heavy meson production in reactions with nuclei is an active new frontier to
understand QCD dynamics and the process of hadronization in nuclear matter.
Measurements in various colliding systems at RHIC and LHC, including Pb-Pb,
Xe-Xe, O-O, p-Pb, and p-O, enable precision tests of the medium-size,
temperature, and mass dependencies of the in-medium parton propagation and
shower formation. We employ a coupled DGLAP evolution framework that takes
advantage of splitting functions recently obtained in soft-collinear effective
theory with Glauber gluons (SCET) and hard thermal loop (HTL)
motivated collisional energy loss effects. With jet quenching effects
constrained to the nuclear modification factor of charged hadrons in Pb-Pb
collisions at 5.02 TeV, we present predictions for light and heavy-meson in
Xe-Xe, O-O and p-Pb collisions at the LHC. We find that the nuclear
modification scales non-trivially with the quark mass and medium properties. In
particular, there can be sizeable collision-induced attenuation of heavy mesons
in small systems such as oxygen-oxygen and high-multiplicity p-Pb events.
Finally, we analyze the impact of different models of initial-state parton
dynamics on the search for QGP signatures in small colliding systems.Comment: Quark Matter 2023 Proceedings; 4 pages, 3 figure