45 research outputs found

    Influence of finite volume effect on the Polyakov Quark-Meson model

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    In the current work, we study the influence of a finite volume on 2+12+1 SU(3)SU(3) Polyakov Quark-Meson model (PQM) order parameters, (fluctuations) correlations of conserved charges and the quark-hadron phase boundary. Our study of the PQM model order parameters and the (fluctuations) correlations of conserved charges indicates a sizable shift of the quark-hadron phase boundary to higher values of baryon chemical potential (μB\mu_{B}) and temperature (TT) for decreasing the system volume. The detailed study of such effect could have important implications for the extraction of the (fluctuations) correlations of conserved charges of the QCD phase diagram from heavy ion data.Comment: 12 pages, 8 figure

    Beam energy and system dependence of rapidity-even dipolar flow

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    New measurements of rapidity-even dipolar flow, v1even^{even}_{1}, are presented for several transverse momenta, pTp_T, and centrality intervals in Au+Au collisions at sNN = 200, 39\sqrt{s_{NN}}~=~200,~39 and 19.619.6 GeV, U+U collisions at sNN = 193\sqrt{s_{NN}}~=~193 GeV, and Cu+Au, Cu+Cu, d+Au and p+Au collisions at sNN = 200\sqrt{s_{NN}}~=~200~GeV. The v1even^{even}_{1} shows characteristic dependencies on pTp_{T}, centrality, collision system and sNN\sqrt{s_{_{NN}}}, consistent with the expectation from a hydrodynamic-like expansion to the dipolar fluctuation in the initial state. These measurements could serve as constraints to distinguish between different initial-state models, and aid a more reliable extraction of the specific viscosity η/s\eta/s

    On SU(3) effective models and chiral phase-transition

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    The sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL) model as an effective theory of quark dynamics to chiral symmetry has been utilized in studying the QCD phase-diagram. Also, Poyakov linear sigma-model (PLSM), in which information about the confining glue sector of the theory was included through Polyakov-loop potential. Furthermore, from quasi-particle model (QPM), the gluonic sector of QPM is integrated to LSM in order to reproduce recent lattice calculations. We review PLSM, QLSM, PNJL and HRG with respect to their descriptions for the chiral phase-transition. We analyse chiral order-parameter M(T), normalized net-strange condensate Delta_{q,s}(T) and chiral phase-diagram and compare the results with lattice QCD. We conclude that PLSM works perfectly in reproducing M(T) and Delta_{q,s}(T). HRG model reproduces Delta_{q,s}(T), while PNJL and QLSM seem to fail. These differences are present in QCD chiral phase-diagram. PLSM chiral boundary is located in upper band of lattice QCD calculations and agree well with freeze-out results deduced from high-energy experiments and thermal models. Also, we find that the chiral temperature calculated from from HRG model is larger than that from PLSM. This is also larger than the freeze-out temperatures calculated in lattice QCD and deduced from experiments and thermal models. The corresponding temperature T and chemical potential mu sets are very similar to that of PLSM. This might be explained, because the chiral T and mu are calculated using different order parameters; in HRG vanishing quark-antiquark condensate but in PLSM crossing (equaling) chiral condensates and Polyakov loop potentials. The latter assumed that the two phase transitions; chiral and deconfinement, take place at the same temperature.Comment: 19 pages, 3 eps-figures accepted for publication in AHE

    Collision system and beam energy dependence of anisotropic flow fluctuations

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    New measurements of two- and four-particle elliptic flow are used to investigate flow fluctuations in collisions of U+U at sNN\sqrt{s_{NN}} = 193~GeV, Cu+Au at sNN\sqrt{s_{NN}} = 200~GeV and Au+Au at several beam energies. These measurements highlight the dependence of these fluctuations on the event-shape, system-size and beam energy and indicate a dominant role for initial-state-driven fluctuations. These measurements could provide further constraints for initial-state models, as well as for precision extraction of the temperature-dependent specific shear viscosity ηs(T)\frac{\eta}{s}(T)