Abstract
The “unreasonable effectiveness” of relativistic fluid dynamics in describing high energy heavy-ion and even proton-proton collisions will be demonstrated and discussed. Several recent ideas of optimizing relativistic fluid dynamics for the specific challenges posed by such collisions will be presented, and some thoughts will be offered why the framework works better than originally expected. I will also address the unresolved question where exactly hydrodynamics breaks down, and why.
Highlights
Gluon plasma created in GG collisions in this imaginary world will look qualitatively similar to that of the quark-gluon plasma created in pp collisions at the real LHC
The quantization of emitted energy in heavy chunks implies that the underlying fluid dynamical behavior cannot be sampled continuously and suffers from finite number statistical fluctuations — even more so in the glueball world than in ours — such that its exploration requires averaging over many similar collision events in order to sample the underlying physics with sufficient statistical precision
While the gluon plasma created in the GG collision of our imaginary glueball world may exhibit almost identical hydrodynamic flow patterns to the quark-gluon plasma in a pp collision at the LHC with the same initial entropy per unit rapidity, these patterns would be much harder to discern in the GG collision, due to much larger finite number statistical fluctuations in the final state
Summary
The absolute value of the (initial) entropy per unit space-time rapidity, dS/dηs = τ0 d2r⊥s(r⊥, η, τ0), on the other hand, which is (on average) monotonically related to the final state charged hadron pseudorapidity density dNch/dη [8], remains well-defined even in strongly-coupled quantum field theories without good quasi-particles, and may be a better starting point for a breakdown criterium of the hydrodynamic paradigm (see, e.g., [7, 9, 10]).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
