119211238
Directed flow of transported and non-transported protons in Au+Au collisions from UrQMD model
The directed flow of inclusive, transported and non-transported (including produced) protons, as well as antiprotons, has been studied in the framework of Ultra-Relativistic Quantum Molecular Dynamics approach (UrQMD model) for Au+Au collisions at √ sNN =7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV. The rapidity, centrality and energy dependence of directed flow for various proton groups are presented. It is found that the integrated directed flow decreases monotonically as a function of collision energy for √ sNN =11.5 GeV and beyond. However, the sign-change of directed flow of inclusive protons, seen in experimental data as a function of centrality and collision energy, can be explained by the competing effect of directed flow between transported and non-transported protons. Similarly the difference in directed flow between protons and antiprotons can be explained. Our study offers a conventional explanation on the cause of the v1 sign-change other than the antiflow component of protons alone which is argued to be linked to a phase transition.
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.
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.
131941483
Selfaffine analysis for the dynamical fluctuations inside jets produced in high-energy hadron hadron collisions
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.
122136554
Unified description of multiplicity distributions of final-state particles produced in collisions at high energies
Abstract The paper presents a modelling description to multiplicity distributions of final-state particles measured in different collision systems at different center-of-mass energies. As examples distributions of charged particles (hadrons) measured in e + e − , pp, p p ¯ , and e + p collisions are presented and good agreement between the calculation and the data is found. Meanwhile, distributions of final-state particles produced in proton and heavy ion induced nuclear collisions are included in the framework of the unified description. The basis of the calculations is a weight sum of different Erlang distributions. The model assumption is that many sources of emitted particles are formed in collisions. Each source contributes multiplicity distribution like a radioactive object.
121985267
PSEUDORAPIDITY DISTRIBUTION SHAPE OF SHOWER PARTICLES IN HIGH ENERGY NUCLEUS-EMULSION COLLISIONS
Abstract The characteristics of the pseudorapidity distribution shape of shower particles produced in high-energy nucleus-emulsion collisions have been studied in this paper. The simple and useful experimental formula, the Gaussian distribution, cannot describe the pseudorapidity distributions with a long tail, two peaks and a plateau. Considering the contributions of the projectile and target protons, the thermalized cylinder picture gives a better description of the experimental data.
122359446
Dependence of elliptic flow on participant nucleon number in Au + Au collisions at sNN=200 GeV
Elliptic flows of charged particles produced in nucleus-nucleus collisions at high energy are studied in the framework of a multisource ideal-gas model. The participant nucleon number at a fixed impact parameter is calculated by a geometrical picture of the participant-spectator model. Then, the dependence of elliptic flow on participant nucleon number is obtained in the combined framework of the two models. Our calculated results are approximately in agreement with the experimental data of the PHENIX Collaboration.
118337659
Transverse-energy distribution in proton?nucleus collisions at high energy
Based on the model of nuclear-collision geometry, the independent NN collision picture and participant contribution picture are used to describe the transverse-energy distribution in pA collisions at high energy. In the independent NN collision picture, the energy loss of leading proton in each pN collision is considered. The calculated results are in agreement with the experimental data of pAl, pCu, and pU collisions at 200 GeV/c. PACS Nos.: 13.85-t, 13.85Hd, 25.75-q
59422650
Transverse Momentum and Pseudorapidity Distributions of Charged Particles and Spatial Shapes of Interacting Events in Pb-Pb Collisions at 2.76 TeV
The transverse momentum and pseudorapidity distributions of charged
particles produced in Pb-Pb collisions with different centrality intervals at center-of-mass
energy per nucleon pair  TeV have been analyzed by using the improved
multisource thermal model in which the whole interacting system and then the sources
are described by the Tsallis statistics. The modelling results are in agreement with experimental data of the ALICE Collaboration. The rapidity distributions of charged particles are obtained according to the extracted parameter values. The shapes of interacting
events (the dispersion plots of charged particles) are given in the momentum, rapidity,
velocity, and coordinate spaces. Meanwhile, the event shapes in different spaces consisted
by different transverse quantities and longitudinal quantities are presented.