Partonic Effects in Heavy Ion Collisions at RHIC

Ko, Che Ming; Lin, Zhibin; Pal, Subrata

doi:10.1556/aph.17.2003.2-4.6

Cited by 11 publications

(11 citation statements)

References 40 publications

(30 reference statements)

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“…The AMPT model [8][9][10][11][12][13]] is a hybrid model that uses minijet partons from hard processes and strings from soft processes in the heavy-ion jet interaction generator (HIJING) model [14] as the initial conditions for modeling heavy-ion collisions at ultrarelativistic energies. Because the initial energy density in Au+Au collisions at RHIC is much larger than the critical energy density at which the hadronic matter to quark-gluon plasma transition would occur [10,13,15], we use the version which allows the melting of initial excited strings into partons [16].…”

Section: A a Brief Reviewmentioning

confidence: 99%

Charm elliptic flow in relativistic heavy-ion collisions

2005

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Charm elliptic flow in heavy-ion collisions at the Relativistic Heavy Ion Collider is studied in a multiphase transport model. Assuming that the cross section for charm quark scattering with other light quarks is the same as that between light quarks, we find that both charm and light quark elliptic flows are sensitive to the value of the cross section. Compared to that of light quarks, the elliptic flow of charm quarks is smaller at low transverse momentum but approaches comparable values at high transverse momentum. Similar features are seen in the elliptic flow of charmed mesons as well as that of the electrons from their semileptonic decays when the charmed mesons are produced from quark coalescence during hadronization of the partonic matter. To describe the large electron elliptic flow observed in available experimental data requires a charm quark-scattering cross section that is much larger than that given by the perturbative quantum chromodynamics.

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Section: A a Brief Reviewmentioning

confidence: 99%

Charm elliptic flow in relativistic heavy-ion collisions

2005

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“…Use is made of both the default version and the version with string melting, that is, a version allowing hadrons that are expected to be formed from initial strings to convert to their valence quarks and antiquarks [10,22,23]. The latter was able to explain the measured p T dependence of v 2 and v 4 of midrapidity charged hadrons with a parton scattering cross section of about 10 mb whereas the default version seemed to give a better description of the anisotropic flows at large rapidities where the string degree of freedom dominates [24].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic flow inCu+Aucollisions atsNN=200GeV

Chen

2006

Phys. Rev. C

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The anisotropic flow of charged hadrons in asymmetric Cu + Au collisions at the Relativistic Heavy Ion Collider is studied in a multiphase transport model. Compared with previous results for symmetric Au + Au collisions, charged hadrons produced around midrapidity in asymmetric collisions are found to have a stronger directed flow v 1 and their elliptic flow v 2 is also more sensitive to the parton scattering cross section. Although higher order flows v 3 and v 4 are small at all rapidities, both v 1 and v 2 in these collisions are appreciable and show an asymmetry in forward and backward rapidities.

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“…Using the version with string melting, i.e., allowing hadrons that are expected to be formed from initial strings to convert to their valence quarks and antiquarks [17][18][19], we find that the measured data from Au+ Au collisions at ͱ s = 200A GeV can be approximately reproduced if a parton scattering cross section of about 10 mb is used in the model. Our results show that the hadron v 4 is indeed a more sensitive probe of the initial partonic dynamics in relativistic heavy-ion collisions than v 2 .…”

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confidence: 99%

Partonic effects on higher-order anisotropic flows in relativistic heavy-ion collisions

Chen

Lin

2004

Phys. Rev. C

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Higher-order anisotropic flows v 4 and v 6 of charged hadrons in heavy-ion collisions at the Relativistic Heavy Ion Collider are studied in a multiphase transport model that has previously been used successfully for describing the elliptic flow v 2 of identified hadrons in these collisions. We find that the same parton scattering cross section of about 10 mb used in explaining the measured v 2 of charged hadrons can also reproduce the recent data on their v 4 and v 6 from Au+ Au collisions at ͱ s = 200A GeV. It is further found that v 4 is a more sensitive probe of the initial partonic dynamics in these collisions than v 2 . Moreover, higher-order parton anisotropic flows are non-negligible and satisfy the scaling relation v n,q ͑p T ͒ϳv 2,q n/2 ͑p T ͒, which leads naturally to the observed similar scaling relation among hadron anisotropic flows when the coalescence model is used to describe hadron production from the partonic matter. There have been extensive studies on the azimuthal anisotropy of hadron momentum distributions in the transverse plane perpendicular to the beam direction, particularly the lower-order elliptic flow v 2 , in heavy-ion collisions at various energies [1]. The hadron transverse momentum anisotropy is generated from the pressure anisotropy in the initial compressed matter formed in noncentral heavy-ion collisions [2,3] and is thus sensitive to the properties of produced matter. This sensitivity not only exists in the larger elliptic flow [4-9] but also in the smaller higher-order anisotropic flows [10][11][12]. Recently, higher-order anisotropic flows v 4 , v 6 , and v 8 in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) were studied in more detail using the hydrodynamical model [13], and it was suggested that v 4 could also provide important information on the collision dynamics during the early stage. Although the hadron anisotropic flows become smaller with increasing orders, recent experimental results from STAR Collaboration [14] have demonstrated that they are still measurable.In the present work, the anisotropic flows v 2 , v 4 , and v 6 of both partons and hadrons in heavy-ion collisions at RHIC are studied in a multiphase transport (AMPT) model that includes initial partonic and final hadronic interactions [15,16]. Using the version with string melting, i.e., allowing hadrons that are expected to be formed from initial strings to convert to their valence quarks and antiquarks [17][18][19], we find that the measured data from Au+ Au collisions at ͱ s = 200A GeV can be approximately reproduced if a parton scattering cross section of about 10 mb is used in the model. Our results show that the hadron v 4 is indeed a more sensitive probe of the initial partonic dynamics in relativistic heavy-ion collisions than v 2 . We also find that higher-order parton anisotropic flows are non-negligible and satisfy the scaling relation v n,q ͑p T ͒ϳv 2,q n/2 ͑p T ͒, which then leads to a similar scaling relation among hadron anisotropic flows when hadron production from the ...

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Partonic Effects in Heavy Ion Collisions at RHIC

Cited by 11 publications

References 40 publications

Charm elliptic flow in relativistic heavy-ion collisions

Charm elliptic flow in relativistic heavy-ion collisions

Anisotropic flow inCu+Aucollisions atsNN=200GeV

Partonic effects on higher-order anisotropic flows in relativistic heavy-ion collisions

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