Effects of Mean-field and Softening of Equation of State on Elliptic Flow in Au+Au Collisions at SNN
Effects of Mean-field and Softening of Equation of State on Elliptic Flow in Au+Au Collisions at SNN

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Published: 2018

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Abstract: We perform a systematic study of elliptic flow ( v 2 ) in Au+Au collisions at s NN = 5 GeV by using a microscopic transport model, JAM. The centrality, pseudorapidity, transverse momentum and beam energy dependence of v 2 for charged as well as identified hadrons are studied. We investigate the effects of both the hadronic mean-field and the softening of equation of state (EoS) on elliptic flow. The softening of the EoS is realized by imposing attractive orbits in two body scattering, which can reduce the pressure of the system. We found that the softening of the EoS leads to the enhancement of v 2, while the hadronic mean-field suppresses v 2 relative to the cascade mode. It indicates that elliptic flow at high baryon density regions is highly sensitive to the EoS and the enhancement of v 2 may probe the signature of a first-order phase transition in heavy-ion collisions at beam energies of a strong baryon stopping region.

Elliptic Flow in Au+Au Collisions at 200 GeV Per Nucleon Pair
Elliptic Flow in Au+Au Collisions at 200 GeV Per Nucleon Pair

Author: Carla Manuel Vale

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Published: 2004

Total Pages: 154

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The Relativistic Heavy Ion Collider (RHIC) has provided its experiments with the most energetic nucleus-nucleus collisions ever achieved in a laboratory. These collisions allow for the study of the properties of nuclear matter at very high temperature and energy density, and may uncover new forms of matter created under such conditions. This thesis presents measurements of the elliptic flow amplitude, v2, in Au+Au collisions at RHIC's top center of mass energy of 200 GeV per nucleon pair. Elliptic flow is interesting as a probe of the dynamical evolution of the system formed in the collision. The elliptic flow dependences on transverse momentum, centrality, and pseudorapidity were measured using data collected by the PHOBOS detector during the 2001 RHIC run. The reaction plane of the collision was determined using the multiplicity detector, and the azimuthal angles of tracks reconstructed in the spectrometer were then correlated with the found reaction plane. The v2 values grow almost linearly with transverse momentum, up to P[sub]T of approximately 1.5 GeV, saturating at about 14%. As a function of centrality, v2 is minimum for central events, as expected from geometry, and increases up to near 7% (for 0

Measurements of Elliptic and Triangular Flow in High-Multiplicity He3+Au Collisions at SNN
Measurements of Elliptic and Triangular Flow in High-Multiplicity He3+Au Collisions at SNN

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Published: 2015

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In this paper, we present the first measurement of elliptic (v2) and triangular (v3) flow in high-multiplicity 3He+Aucollisions at √sNN=200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in 3He+Au and in p+p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the 3He+Ausystem. The collective behavior is quantified in terms of elliptic v2 and triangular v3 anisotropy coefficients measured with respect to their corresponding event planes. The v2 values are comparable to those previously measured in d+Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three 3He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. Finally, the agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.

Measurements of Elliptic and Triangular Flow in High-multiplicity 3He+Au Collisions at {u221A}sNN
Measurements of Elliptic and Triangular Flow in High-multiplicity 3He+Au Collisions at {u221A}sNN

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Published: 2015

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We present the first measurement of elliptic (v2) and triangular (v3) flow in high-multiplicity 3He+Aucollisions at √sNN=200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in 3He+Au and in p+p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the 3He+Ausystem. The collective behavior is quantified in terms of elliptic v2 and triangular v3 anisotropy coefficients measured with respect to their corresponding event planes. The v2 values are comparable to those previously measured in d+Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three 3He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.

Centrality Dependence of Identified Particle Elliptic Flow in Relativistic Heavy Ion Collisions at [math][mrow][msqrt][msub][mi][/mi][mrow][mi]N[/mi][mi]N[/mi][/mrow][/msub][/msqrt][mo]
Centrality Dependence of Identified Particle Elliptic Flow in Relativistic Heavy Ion Collisions at [math][mrow][msqrt][msub][mi][/mi][mrow][mi]N[/mi][mi]N[/mi][/mrow][/msub][/msqrt][mo]

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Published: 2016

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Here, elliptic flow (v2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at √sNN = 7.7-62.4 GeV are presented for three centrality classes. The centrality dependence and the data at √sNN = 14.5 GeV are new. Except at the lowest beam energies, we observe a similar relative v2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with a multiphase transport (AMPT) model and fit with a blast wave model.