GL（马国亮） Ma

Di-hadron azimuthal correlation and Mach-like cone structure in a parton/hadron transport model

Abstract In the framework of a multi-phase transport model (AMPT) with both partonic and hadronic interactions, azimuthal correlations between trigger particles and associated scattering particles have been studied by the mixing-event technique. The momentum ranges of these particles are 3 p T trig 6 GeV / c and 0.15 p T assoc 3 GeV / c (soft), or 2.5 p T trig 4 GeV / c and 1 p T assoc 2.5 GeV / c (hard) in Au + Au collisions at s N N = 200 GeV . A Mach-like structure has been observed in correlation functions for central collisions. By comparing scenarios with and without parton cascade and hadronic rescattering, we show that both partonic and hadronic dynamical mechanisms contribute to the Mach-like structure of the associated particle azimuthal correlations. The contribution of hadronic dynamical process cannot be ignored in the emergence of Mach-like correlations of the soft scattered associated hadrons. However, hadronic rescattering alone cannot reproduce experimental amplitude of Mach-like cone on away-side, and the parton cascade process is essential to describe experimental amplitude of Mach-like cone on away-side. In addition, both the associated multiplicity and the sum of p T decrease, while the 〈 p T 〉 increases, with the impact parameter in the AMPT model including partonic dynamics from string melting scenario.

System size and energy dependence of near side dihadron correlations

Two-particle azimuthal (Delta phi) and pseudorapidity (Delta eta) correlations using a trigger particle with large transverse momentum (p(T)) in d+Au, Cu+Cu, and Au+Au collisions at root s(NN) = 62.4 GeV and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider are presented. The near-side correlation is separated into a jet-like component, narrow in both Delta phi and Delta eta, and the ridge, narrow in Delta phi but broad in Delta eta. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated p(T). The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at root s(NN) = 200 GeV, is also found in Cu+Cu collisions and in collisions at root s(NN) = 62.4 GeV, but is found to be substantially smaller at root s(NN) = 62.4 GeV than at root s(NN) = 200 GeV for the same average number of participants ( ). Measurements of the ridge are compared to models.

What is the origin of a Mach-like cone structure in parton cascade?

In order to search for the origin of a Mach-like cone structure in parton cascade, a γ-jet with a known production point and momentum is triggered in a multi-phase transport model. The medium response is sensitive to the geometry configuration between the triggered γ-jet and medium. The origin of a Mach-like cone structure is a strong shadowing effect of dense core, which is related to transverse expansion and radial flow of partonic matter. Because the cone structure formed by a triggered bottom jet in parton cascade does not obey the Mach cone law, it is not a Mach cone.

Strange-quark collectivity of the φ-meson at RHIC

Abstract.Based on A Multi-Phase Transport (AMPT) model, the elliptic flow v2 of φ-mesons which is reconstructed from K+K- at the Relativistic Heavy-Ion Collider (RHIC) energy has been studied. The results show that the reconstructed v2 of the φ-meson can keep the earlier information before φ decays and it seems to obey the number of constituent-quark scaling as other mesons and baryons. This result indicates that the φ v2 mostly reflects the parton level collectivity developed during the early stage of the collisions and the strange and light up/down quarks have similar collectivity properties before the hadronization.

Possible exotic structure in light proton-rich nuclei

Radioactive ion beams were produced through the projectile fragmentation induced by 69MeV/nucleon 36Ar primary beam on a 9Be target. Measurements of reaction cross section (σR) for some proton-rich nuclei on carbon target at intermediate energies around 30MeV/nucleon have been performed on RIBLL of HIRFL by transmission method and transmission plus transportation method. The experimental σR values for 23Al and 27P are abnormally large compared with their neighboring nuclei and that of 17F has an enhancement compared with the neighboring isotopes. It suggests anomalously large matter root-mean-square radii and proton halo structure in 23Al and 27P. The experimental σR values and momentum distribution of fragmentation reaction product for 31Cl, 32Cl, 33Cl, 28S, 29S were performed also on RIBLL by transmission and transportation method. These data are in analyzing. The calculation of relativistic density-dependent Hartree shows that the nuclei 23Al, 27P, 31Cl may have proton-halo structure and 17F, 32Cl may ...

Measurements of D-0 and D* production in p plus p collisions at root s=200 GeV

We report measurements of charmed-hadron (

Stability of (1+1)-dimensional causal relativistic viscous hydrodynamics

D^{0}

Strange quark dynamics on hot dense matter under the extreme condition

,

Effects of bulk viscosity on hadron spectra and the Hanbury-Brown Twiss radius by causal viscous hydrodynamics

D^{*}

Temperature fluctuation and heat capacities of quarks and pi meson

) production cross sections at mid-rapidity in