123192244
Orientation dependence of center baryon density in central 0.52 GeV/n U-U collisions
With a relativistic transport model, We performed simulation for deformed UU collision with vast different orientation at CSR energy area corresponding to the high net-baryon density region in QCD phase diagram. By investigating the centrality and initial collision orientation dependence of the baryon density form, we found that those tip-tip like UU collisions with extended high density phase, which is very important for studying the nuclear EoS of high baryon density matter and the possible end-point of the phase boundary, are those events with small orientations (< 20°) in reaction plane and small impact parameter (< 2.4 fm). We have developed a measurable quantity that allows us to select those most interesting events (i.e. tip-tip like) in the experiment.
118652542
Study of triangular flow v3 in Au+Au and Cu+Cu collisions with a multiphase transport model
We studied the relation between the initial geometry anisotropy and the anisotropic flow in a multiphase transport model for both Au+Au and Cu+Cu collisions at = 200 GeV. It is found that unlike the elliptic flow v2, little centrality dependence of the triangular flow v3 is observed. After removing the initial geometry effect, v3/e3 increases with the transverse particle density, which is similar to v2/e2. The transverse momentum (pT) dependence of v3 from identified particles is qualitatively similar to the pT dependence of v2.
15711757
Thermal Equilibrium and Non-uniform Longitudinal Flow in Relativistic Heavy Ion Collisions
A model with non-uniform flow in the longitudinal direction is proposed for the relativistic heavy-ion collisions and compared with the 14.6 A GeV/c Si-Al and 10.8 A GeV/c Au-Au collision data. The stronger influence of transparency on the distribution of heavier produced particles and the larger stopping in the heavier collision system are accounted for by using a new geometrical parameterization picture. The central dips in the proton and deuteron rapidity distributions for Si-Al collision are reproduced.
120498489
Elliptic flow in a hadron transport model
We present elliptic flow v2 as a function of freeze-out time, transverse momentum for π, K, nucleon, Λ, Ξ and Ω in Au+Au collisions at within two transport approaches (RQMD and UrQMD). The presence of mass ordering and NCQ scaling in the string-hadron model suggests that hadronic interactions do contribute to the observed particle-type dependence of v2 as well.
1752055
On transverse momentum event–by–event fluctuations in string hadronic models
Abstract. Transverse momentum event–by–event fluctuations are studied within the string–hadronic model of high energy nuclear collisions, LUCIAE. Data on non–statistical $p_T$ fluctuations in p+p interactions are reproduced. Fluctuations of similar magnitude are predicted for nucleus–nucleus collisions, in contradiction to the preliminary NA49 results. The introduction of a string clustering mechanism (Firecracker Model) leads to a further, significant increase of $p_T$ fluctuations for nucleus–nucleus collisions. Secondary hadronic interactions, as implemented in LUCIAE, cause only a small reduction of $p_T$ fluctuations.
17224426
New results for hadronic collisions in the framework of the Parton-Based Gribov-Regge Theory
Abstract We recently proposed a new approach to high energy nuclear scattering, which treats hadronic collisions in a sophisticated way. Demanding theoretical consistency as a minimal requirement for a realistic model, we provide a solution for the energy conservation, screening problems and identical elementary interactions, the so-called “Parton-Based Gribov-Regge Theory” including enhanced diagrams. We can now present some of our results for SPS and RHIC energies.
122895317
Dependence of charged particle pseudorapidity distributions on centrality and energy in p(d)A collisions at high energies
The pseudorapidity distributions of charged particles produced in deuteron-gold (d-Au) and proton-emulsion (p-Em) collisions at high energies are studied in the framework of the two-cylinder model. The experimental results of nuclear reactions induced by protons and deuterons [p(d)A collisions] can be simply described by this model. The dependencies of parameter values on centrality for d-Au collisions and on nucleon-nucleon center-of-mass energy for p-Em collisions are obtained. The formula obtained by this model is a unified formula in the description of (pseudo)rapidity distributions of final-state particles produced in different interactions over an energy range from intermediate accelerator energy to ultrahigh cosmic-ray energy.
122547143
Net-proton emission in nucleus-nucleus collisions at high energies
The transverse momentum spectrum and rapidity distribution of net-protons produced in nucleus-nucleus collisions at high energies have been studied by using a two-cylinder model. The calculated results are compared and found to be in agreement with the experimental data of Au-Au collisions at the RHIC and AGS energies, as well as Pb-Pb and S-S collisions at the SPS energies. Linear correlations between the parameters in the model and the logarithmic center-of-mass energy are found.
121373435
Investigation of correlations between conditional moments in nuclear fragmentation at high energy
The conditional moments of the charge distributions of the projectile fragments in O and S fragmentation are obtained using the partition method. Thus, the logarithmic correlations between the conditional moments can be observed. The electromagnetic dissociations are similar to the correlation behaviour of nuclear reactions. This is illustrated by the correlation behaviour of the oxygen nuclei, which are in agreement with that of the sulphur nuclei. The calculated results correspond to the experimental data of 3.7 and 200 GeV N−1 O–Em and 200 GeV N−1 S–Em interactions.
121392052
Multiple particle production in proton-proton collisions at energies available at the Large Hadron Collider
A shift three-source model is used in this paper to describe the multiplicity and the pseudorapidity distributions of final-state charged particles produced in proton-proton collisions at energies available at the Large Hadron Collider (LHC). The three kinds of sources are central sources arising from gluon-gluon collisions, target fragmentation sources arising from gluon- or quark-induced collisions with target quarks, and projectile fragmentation sources arising from gluon- or quark-induced collisions with projectile quarks. The central, target fragmentation, and projectile fragmentation sources each have shifts around their centers. The results calculated by using the shift three-source model are in agreement with the experimental data of the ALICE (A Large Ion Collider Experiment) and the CMS (Compact Muon Solenoid experiment) Collaborations.
118718956
Dependence of elliptic flow on transverse momentum in $\sqrt{\mathrm{\it s_{NN}}}=200$ GeV Au-Au and $\sqrt{\mathrm{\it s_{NN}=2.76$ TeV Pb-Pb collisions
We investigate the dependence of elliptic flows $v_2$ on transverse momentum $P_T$ for charged hadrons produced in nucleus-nucleus collisions at high energy by using a multi-source ideal gas model which includes the interaction contribution of the emission sources. Our calculated results are approximately in agreement with the experimental data over a wider $P_T$ range from the STAR and ALICE Collaborations. It is found that the expansion factor increases linearly with the impact parameter from most central (0-5%) to mid-peripheral (35-40%) collisions.