scholarly journals Geometric relation between centrality and the impact parameter in relativistic heavy-ion collisions

2002 ◽  
Vol 65 (2) ◽  
Author(s):  
Wojciech Broniowski ◽  
Wojciech Florkowski
Particles ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 275-287
Author(s):  
Petr Parfenov ◽  
Dim Idrisov ◽  
Vinh Ba Luong ◽  
Arkadiy Taranenko

The size and evolution of the matter created in relativistic heavy-ion collisions strongly depend on collision geometry, defined by the impact parameter. However, the impact parameter cannot be measured directly in an experiment but might be inferred from final state observables using the centrality procedure. We present the procedure of centrality determination for the Multi-Purpose Detector (MPD) at the NICA collider and its performance using the multiplicity of produced charged particles at midrapidity. The validity of the procedure is assessed using the simulated data for Au + Au collisions at sNN = 4–11 GeV.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Gao-Feng Wei ◽  
Guo-Qiang He ◽  
Xin-Wei Cao ◽  
Yi-Xin Lu

The impact parameter dependence ofπ-/π+ratio is examined in heavy-ion collisions at 400 MeV/nucleon within a transport model. It is shown that the sensitivity ofπ-/π+ratio on symmetry energy shows a transition from central to peripheral collisions; that is, the stiffer symmetry energy leads to a largerπ-/π+ratio in peripheral collisions while the softer symmetry energy always leads this ratio to be larger in central collisions. After checking the kinematic energy distribution ofπ-/π+ratio, we found this transition of sensitivity ofπ-/π+ratio to symmetry energy is mainly from less energetic pions; that is, the softer symmetry energy gets the less energetic pions to form a smallerπ-/π+ratio in peripheral collisions while these pions generate a largerπ-/π+ratio in central collisions. Undoubtedly, the softer symmetry energy can also lead more energetic pions to form a largerπ-/π+ratio in peripheral collisions. Nevertheless, considering that most of pions are insufficiently energetic at this beam energy, we therefore suggest theπ-/π+ratio as a probe of the high-density symmetry energy effective only in central at most to midcentral collisions, thereby avoiding the possible information of low-density symmetry energy carried inπ-/π+ratio from peripheral collisions.


1999 ◽  
Vol 60 (5) ◽  
Author(s):  
A. Grünschloß ◽  
K. Boretzky ◽  
T. Aumann ◽  
C. A. Bertulani ◽  
J. Cub ◽  
...  

1991 ◽  
Vol 46 (12) ◽  
pp. 1037-1042 ◽  
Author(s):  
G. Wolschin

Abstract Mean transit times in heavy-ion collisions are calculated as functions of the relativistic incident energy and the impact parameter. As a consequence of special relativity, they become constant in a central collision of O with Pb at T~0.15TeV. Together with a geometrical estimate of the maximum energy densities in the interaction region, it is argued that heavy ions in a large hadron collider may produce a quark-gluon plasma due to the plateau in the transit times at ultra-relativistic energies


2019 ◽  
Vol 223 ◽  
pp. 01050
Author(s):  
Silvia Piantelli ◽  
Alessandro Olmi ◽  
Paolo R. Maurenzig ◽  
Akira Ono ◽  
Maurizio Bini ◽  
...  

The simulation of heavy ion collisions in the Fermi energy region is a challenge for the theoretical models; in particular it is difficult to obtain a coherent description in all the impact parameter range and to reproduce all the experimental observables. In this contribution we will show the very good job done by the dynamical model AMD [1] followed by the statistical code GEMINI [2, 3] as an afterburner. The model is able to reproduce the main characteristics of peripheral and semiperipheral collisions, although some discrepancies still persist.


1994 ◽  
Vol 107 (5) ◽  
pp. 697-711
Author(s):  
A. Del Zoppo ◽  
C. Agodi ◽  
R. Alba ◽  
G. Bellia ◽  
R. Coniglione ◽  
...  

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