PARTICLE IDENTIFICATION IN THE DYNAMICAL STRING-PARTON MODEL OF RELATIVISTIC HEAVY-ION COLLISIONS

1999 ◽  
Vol 08 (04) ◽  
pp. 299-309 ◽  
Author(s):  
D. E. MALOV ◽  
A. S. UMAR ◽  
D. J. ERNST ◽  
D. J. DEAN
Keyword(s):  
Heavy Ion Collisions ◽  
Parton Model ◽  
Heavy Ion ◽  
Particle Identification ◽  
Relativistic Heavy Ion Collisions ◽  
Mass Window ◽  
Final State ◽  
Ion Collisions ◽  
Physical Mass ◽  
The Masses

The dynamical string-parton model for relativistic heavy-ion collisions is generalized to include particle identification of the final-state hadrons by phenomenologically quantizing the masses of the classical strings which result from string breaking. General features of the Nambu-Gotō strings are used to motivate a model that identifies a mass window near the physical mass of a meson, and does not allow the string to decay further if its mass falls within the window. Data from e+e- collisions in the region [Formula: see text] to 30 GeV are well reproduced by this model.

scholarly journals Production of $$^4\mathrm{Li}$$ and $$p\!-\!^3\mathrm{He}$$ correlation function in relativistic heavy-ion collisions

2020 ◽  
Vol 56 (7) ◽  
Author(s):  
Sylwia Bazak ◽  
Stanisław Mrówczyński
Keyword(s):  
Correlation Function ◽  
Heavy Ion Collisions ◽  
Coulomb Repulsion ◽  
Heavy Ion ◽  
Light Nuclei ◽  
Relativistic Heavy Ion Collisions ◽  
Weakly Bound ◽  
Ion Collisions ◽  
Internal Structures ◽  
The Masses

Abstract The thermal and coalescence models both describe well yields of light nuclei produced in relativistic heavy-ion collisions at LHC. We propose to measure the yield of $$^4\mathrm{Li}$$ 4 Li and compare it to that of $$^4\mathrm{He}$$ 4 He to falsify one of the models. Since the masses of $$^4\mathrm{He}$$ 4 He and $$^4\mathrm{Li}$$ 4 Li are almost equal, the yield of $$^4\mathrm{Li}$$ 4 Li is about 5 times bigger than that of $$^4\mathrm{He}$$ 4 He in the thermal model because of different numbers of spin states of the two nuclides. Their internal structures are, however, very different: the alpha particle is well bound and compact while $$^4\mathrm{Li}$$ 4 Li is weakly bound and loose. Consequently, the ratio of yields of $$^4\mathrm{Li}$$ 4 Li to $$^4\mathrm{He}$$ 4 He is significantly smaller in the coalescence model and it strongly depends on the collision centrality. Since the nuclide $$^4\mathrm{Li}$$ 4 Li is unstable and it decays into $$^3\mathrm{He}$$ 3 He and p, the yield of $$^4\mathrm{Li}$$ 4 Li can be experimentally obtained through a measurement of the $$p\!-\!^3\mathrm{He}$$ p - 3 He correlation function. The function carries information not only about the yield of $$^4\mathrm{Li}$$ 4 Li but also about the source of $$^3\mathrm{He}$$ 3 He and allows one to determine through a source-size measurement whether of $$^3\mathrm{He}$$ 3 He is directly emitted from the fireball or it is formed afterwards. We compute the correlation function taking into account the s-wave scattering and Coulomb repulsion together with the resonance interaction responsible for the $$^4\mathrm{Li}$$ 4 Li nuclide. We discuss how to infer information about an origin of $$^3\mathrm{He}$$ 3 He from the correlation function, and finally a method to obtain the yield of $$^4\mathrm{Li}$$ 4 Li is proposed.

DYNAMICAL CALCULATION OF CENTRAL ENERGY DENSITIES IN RELATIVISTIC HEAVY-ION COLLISIONS

1993 ◽  
Vol 02 (03) ◽  
pp. 565-573 ◽  
Author(s):  
D.J. DEAN ◽  
A.S. UMAR ◽  
M.R. STRAYER
Keyword(s):  
Heavy Ion Collisions ◽  
Transverse Energy ◽  
Parton Model ◽  
Heavy Ion ◽  
Maximum Energy ◽  
Relativistic Heavy Ion Collisions ◽  
Energy Distributions ◽  
Ion Collisions ◽  
Dynamical Calculation ◽  
Central Energy

The 3+1 dimensional string-parton model is used to calculate energy densities and temperatures of produced mesons during relativistic heavy-ion collisions. We compare maximum energy densities with the experimental estimates obtained from the Bjørken formula. Although the string-parton model reproduces transverse energy distributions, dET/dη, the dynamical energy densities of the produced mesons are three to four times smaller than estimates based on the Bjørken formula with a formation time of 1 fm/c. We discuss various time scales which contribute to this discrepancy and suggest a modified interpretation of the Bjørken formula.

scholarly journals Production of light nuclei at colliders – coalescence vs. thermal model

2020 ◽  
Vol 229 (22-23) ◽  
pp. 3559-3583
Author(s):  
Stanisław Mrówczyński
Keyword(s):  
Correlation Function ◽  
Thermal Model ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Light Nuclei ◽  
Relativistic Heavy Ion Collisions ◽  
Final State ◽  
Coalescence Model ◽  
Ion Collisions ◽  
Final State Interactions

AbstractThe production of light nuclei in relativistic heavy-ion collisions is well described by both the thermal model, where light nuclei are in equilibrium with hadrons of all species present in a fireball, and by the coalescence model, where light nuclei are formed due to final-state interactions after the fireball decays. We present and critically discuss the two models and further on we consider two proposals to falsify one of the models. The first proposal is to measure a yield of exotic nuclide 4Li and compare it to that of 4He. The ratio of yields of the nuclides is quite different in the thermal and coalescence models. The second proposal is to measure a hadron-deuteron correlation function which carries information whether a deuteron is emitted from a fireball together with all other hadrons, as assumed in the thermal model, or a deuteron is formed only after nucleons are emitted, as in the coalescence model. The p − 3He correlation function is of interest in context of both proposals: it is needed to obtain the yield of 4Li which decays into p and 3He, but the correlation function can also tell us about an origin of 3He.

scholarly journals Relating Charged Particle Multiplicity to Impact Parameter in Heavy-Ion Collisions at NICA Energies

Particles ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 275-287
Author(s):  
Petr Parfenov ◽  
Dim Idrisov ◽  
Vinh Ba Luong ◽  
Arkadiy Taranenko
Keyword(s):  
Impact Parameter ◽  
Heavy Ion Collisions ◽  
Simulated Data ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Final State ◽  
Ion Collisions ◽  
The Impact

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.

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