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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Bulk quantities in nuclear collisions from running-coupling k(T) factorization and hybrid simulations

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Giannini, V, Andre ; Grassi, Frederique [1] ; Luzum, Matthew [1]
Total Authors: 3
[1] Giannini, Andre, V, Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05508090 Sao Paulo, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Physical Review C; v. 100, n. 1 JUL 31 2019.
Web of Science Citations: 0

Starting from a color glass condensate (CGC) framework, based on a running-coupling improved k T -factorized formula, we calculate bulk observables in several heavy-ion collision systems. This is done in two ways: first we calculate the particle distribution directly implied from the CGC model, and we compare this to the case where it is instead used as the initial condition for a hybrid hydrodynamic simulation. In this way, we can assess the effects of hydrodynamic and hadronic evolution by quantifying how much they change the results from a pure initial state approach and, therefore, to what extent initial condition models can be directly compared to experimental data. We find that entropy production in subsequent hydrodynamic evolution can increase multiplicity by as much as 50%. However, disregarding a single overall normalization factor, the centrality, energy, and system size dependencies of charged hadron multiplicity are only affected at the similar to 5% level. Because of this, the parameter-free prediction for these dependencies gives reasonable agreement with experimental data whether or not hydrodynamic evolution is included. On the other hand, our model results are not compatible with the hypothesis that hydrodynamic evolution is present in large systems, but not in small systems like p-Pb, in which case the dependence of multiplicity on system size would be stronger than seen experimentally. Moreover, we find that hydrodynamic evolution significantly changes the distribution of momentum, so that observables such as the mean transverse momentum are very different from the initial particle production and much closer to measured data. Finally, we find that a good agreement to anisotropic flow data cannot be achieved due to the large eccentricity generated by this model. (AU)

FAPESP's process: 18/23677-0 - Early-time dynamics of hadronic collisions beyond the Gaussian approximation of the Color Glass Condensate
Grantee:André Veiga Giannini
Support type: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 17/14974-8 - Phenomenology of relativistic heavy-ion collisions: QCD under extreme conditions
Grantee:André Veiga Giannini
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 17/05685-2 - Hadronic physics in high energy nuclear collisions
Grantee:Jun Takahashi
Support type: Research Projects - Thematic Grants
FAPESP's process: 16/24029-6 - Investigating the strong nuclear interactions under extreme conditions
Grantee:Matthew William Luzum
Support type: Research Grants - Young Investigators Grants