Search results

1

Di-lepton production in heavy-ion collisions and the QCD phase diagram

100%

Zhang Y., Xu H., Zha W., Wang Q.

Open Physics

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2012

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vol. 10

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issue 6

1352-1356

EN

We reproduce di-electron spectra in the region of 0 < m e+e < 4 GeV in both minimum bias and central Au+Au collisions at $\sqrt {s_{NN} } $ = 200 GeV measured by the STAR experiment. A cocktail simulation, incorporating STAR acceptance and detector responses, is able to describe the “enhancement” of the low mass region by including an in-medium modification of vector mesons and a thermal di-lepton calculation. We also predict the di-lepton mass spectra in RHIC lower energies via an extrapolation method. The evolution of Di-lepton mass spectra, effective temperature, and possible medium modifications versus colliding energies are studied to explore the QCD phase diagram.

2

Resonance states in an effective chiral hadronic model

100%

Rau P., Steinheimer J., Schramm S., Stöcker H.

Open Physics

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2012

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vol. 10

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issue 6

1302-1305

EN

With an effective chiral flavour SU(3) model we show the effect of hadronic resonances on the QCD phase diagram. We state that varying the resonance couplings to the scalar and vector fields affects the order and location of the phase transition, the possible existence of a critical end point (CEP), and the thermodynamic properties. We present (strange) quark number susceptibilities at zero baryochemical potential and at three different points at the phase transition. Comparing results to lattice QCD, we state that reasonable large vector couplings limit the phase transition to a smooth crossover ruling out a CEP.

3

Centrality dependence of freeze-out parameters from Au+Au collisions at $\sqrt {s_{NN} } $ = 7.7, 11.5 and 39 GeV

88%

Kumar L.

Open Physics

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2012

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vol. 10

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issue 6

1274-1277

EN

The RHIC beam energy scan program in its first phase collected data for Au+Au collisions at beam energies of 7.7, 11.5 and 39 GeV. The event statistics collected at these lower energies allow us to study the centrality dependence of various observables in detail, and compare to fixed-target experiments at SPS for similar beam energies. The chemical and kinetic freeze-out parameters can be extracted from the experimentally measured yields of identified hadrons within the framework of thermodynamical models. These then provide information about the system at the stages of the expansion where inelastic and elastic collisions of the constituents cease. We present the centrality dependence of freeze-out parameters for Au+Au collisions at midrapidity for $\sqrt {s_{NN} } $ = 7.7, 11.5, and 39 GeV from the STAR experiment. The chemical freeze-out conditions are obtained by comparing the measured particle ratios (involving π, K, p, and p) to those from the statistical thermal model calculations. The kinetic freeze-out conditions are extracted at these energies by simultaneously fitting the invariant yields of identified hadrons (π, K, and p) using Blast Wave model calculations.

Refine search results

3 Open Physics

3 2012

1 Kumar L.

1 Rau P.

1 Schramm S.

1 Steinheimer J.

1 Stöcker H.

1 Wang Q.

1 Xu H.

1 Zha W.

1 Zhang Y.

Di-lepton production in heavy-ion collisions and the QCD phase diagram

Resonance states in an effective chiral hadronic model

Centrality dependence of freeze-out parameters from Au+Au collisions at $\sqrt {s_{NN} } $ = 7.7, 11.5 and 39 GeV