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Nearly isentropic flow at sizeable $\eta/s$
Non-linearities in the harmonic spectra of hadron-nucleus and nucleus-nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-st...
Autores principales: | , , |
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Lenguaje: | eng |
Publicado: |
2018
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Materias: | |
Acceso en línea: | https://dx.doi.org/10.1016/j.physletb.2018.06.064 http://cds.cern.ch/record/2307389 |
_version_ | 1780957629114220544 |
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author | Kurkela, Aleksi Wiedemann, Urs Achim Wu, Bin |
author_facet | Kurkela, Aleksi Wiedemann, Urs Achim Wu, Bin |
author_sort | Kurkela, Aleksi |
collection | CERN |
description | Non-linearities in the harmonic spectra of hadron-nucleus and nucleus-nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction ("one-hit dynamics"), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ($\sim 50 \%$ centrality) PbPb or central pPb collisions. The shear viscosity to entropy density ratio $\eta/s$ of such a transport theory is approximately an order of magnitude larger than that of an almost perfect fluid. The phenomenological success of transport simulations thus challenges the perfect fluid paradigm of ultra-relativistic nucleus-nucleus and hadron-nucleus collisions. |
id | cern-2307389 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2018 |
record_format | invenio |
spelling | cern-23073892019-10-04T11:35:41Zdoi:10.1016/j.physletb.2018.06.064http://cds.cern.ch/record/2307389engKurkela, AleksiWiedemann, Urs AchimWu, BinNearly isentropic flow at sizeable $\eta/s$nucl-thNuclear Physics - Theorynucl-exNuclear Physics - Experimenthep-exParticle Physics - Experimenthep-phParticle Physics - PhenomenologyNon-linearities in the harmonic spectra of hadron-nucleus and nucleus-nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction ("one-hit dynamics"), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ($\sim 50 \%$ centrality) PbPb or central pPb collisions. The shear viscosity to entropy density ratio $\eta/s$ of such a transport theory is approximately an order of magnitude larger than that of an almost perfect fluid. The phenomenological success of transport simulations thus challenges the perfect fluid paradigm of ultra-relativistic nucleus-nucleus and hadron-nucleus collisions.Non-linearities in the harmonic spectra of hadron–nucleus and nucleus–nucleus collisions provide evidence for the dynamical response to azimuthal spatial eccentricities. Here, we demonstrate within the framework of transport theory that even the mildest interaction correction to a picture of free-streaming particle distributions, namely the inclusion of one perturbatively weak interaction (“one-hit dynamics”), will generically give rise to all observed linear and non-linear structures. We further argue that transport theory naturally accounts within the range of its validity for realistic signal sizes of the linear and non-linear response coefficients observed in azimuthal momentum anisotropies with a large mean free path of the order of the system size in peripheral ( ∼50% centrality) PbPb or central pPb collisions. As a non-vanishing mean free path is indicative of non-minimal dissipation, this challenges the perfect fluid paradigm of ultra-relativistic nucleus–nucleus and hadron–nucleus collisions.CERN-TH-2018-045arXiv:1803.02072oai:cds.cern.ch:23073892018-03-06 |
spellingShingle | nucl-th Nuclear Physics - Theory nucl-ex Nuclear Physics - Experiment hep-ex Particle Physics - Experiment hep-ph Particle Physics - Phenomenology Kurkela, Aleksi Wiedemann, Urs Achim Wu, Bin Nearly isentropic flow at sizeable $\eta/s$ |
title | Nearly isentropic flow at sizeable $\eta/s$ |
title_full | Nearly isentropic flow at sizeable $\eta/s$ |
title_fullStr | Nearly isentropic flow at sizeable $\eta/s$ |
title_full_unstemmed | Nearly isentropic flow at sizeable $\eta/s$ |
title_short | Nearly isentropic flow at sizeable $\eta/s$ |
title_sort | nearly isentropic flow at sizeable $\eta/s$ |
topic | nucl-th Nuclear Physics - Theory nucl-ex Nuclear Physics - Experiment hep-ex Particle Physics - Experiment hep-ph Particle Physics - Phenomenology |
url | https://dx.doi.org/10.1016/j.physletb.2018.06.064 http://cds.cern.ch/record/2307389 |
work_keys_str_mv | AT kurkelaaleksi nearlyisentropicflowatsizeableetas AT wiedemannursachim nearlyisentropicflowatsizeableetas AT wubin nearlyisentropicflowatsizeableetas |