Free energy of a baryon at finite temperatures and its implications to the heavy-ion collisions

2015 ◽  
Vol 30 (26) ◽  
pp. 1550130
Author(s):  
Minati Biswal ◽  
Sanatan Digal ◽  
P. S. Saumia

We study the free energy per baryon using canonical formalism in the Polyakov loop Nambu–Jona-Lasinio model with imaginary chemical potential. We find that the free energy decreases rapidly with temperature around the transition temperature. This result coupled with the heavy-ion collision geometry leads to the creation of a free energy well for the baryons. We study the time evolution of this free energy well using hydrodynamic simulations and discuss the implications of this free energy well on the dynamics of the baryons.

2021 ◽  
Vol 19 (2) ◽  
pp. 61-65
Author(s):  
Taghreed A. Younis ◽  
Hadi J.M. Al-Agealy

This work involves hard photon rate production from quark -gluon plasma QGP interaction in heavy ion collision. Using a quantum chromodynamic model to investigate and calculation of photons rate in 𝑐𝑔 → 𝑠𝑔𝛾 system due to strength coupling, photons rate, temperature of system, flavor number and critical. The photons rate production computed using the perturbative strength models for QGP interactions. The strength coupling was function of temperature of system, flavor number and critical temperature. Its influenced by force with temperature of system, its increased with decreased the temperature and vice versa. The strength coupling has used to examine the confinement and deconfinement of quarks in QGP properties and influence on the photon rate production. In our approach, we calculate the photons rate depending on the strength coupling, photons rate and temperature of system with other factors. The results plotted as a function of the photons energy. The photons rate was decreased with increased temperature and increased with decreased with strength coupling.


2020 ◽  
Vol 12 (2) ◽  
pp. 215-221
Author(s):  
P. K. Sethy ◽  
Y. Kumar ◽  
S. S. Singh

It is believed that a transient strong magnetic field is generated in heavy-ion collision. The strength of this field perpendicular to the reaction plane and is estimated to be around eB=0.03GeV2 at RHIC and eB=0.3GeV2 at LHC. We study the effect of this magnetic field on dilepton yield using a modified quasi particle model. The results show a clear enhancement in dilepton yield and our result is in good agreement with the recently reported results.


2017 ◽  
Vol 32 (13) ◽  
pp. 1750067 ◽  
Author(s):  
Zan Pan ◽  
Zhu-Fang Cui ◽  
Chao-Hsi Chang ◽  
Hong-Shi Zong

To investigate the finite-volume effects on the chiral symmetry restoration and the deconfinement transition for a quantum chromodynamics (QCD) system with [Formula: see text] (two quark flavors), we apply the Polyakov-loop extended Nambu–Jona-Lasinio model by introducing a chiral chemical potential [Formula: see text] artificially. The final numerical results indicate that the introduced chiral chemical potential does not change the critical exponents, but shifts the location of critical end point (CEP) significantly; the ratios for the chiral chemical potentials and temperatures at CEP, [Formula: see text] and [Formula: see text], are significantly affected by the system size [Formula: see text]. The behavior is that [Formula: see text] increases slowly with [Formula: see text] when [Formula: see text] is “large” and [Formula: see text] decreases first and then increases with [Formula: see text] when [Formula: see text] is “small.” It is also found that for a fixed [Formula: see text], there is a [Formula: see text], where the critical end point vanishes and the whole phase diagram becomes a crossover when [Formula: see text]. Therefore, we suggest that for the heavy-ion collision experiments, which is to study the possible location of CEP, the finite-volume behavior should be taken into account.


2021 ◽  
pp. 2150152
Author(s):  
Abhisek Saha ◽  
Soma Sanyal

In this paper, we study temperature fluctuations in the initial stages of the relativistic heavy ion collision using a multiphase transport model. We consider the plasma in the initial stages after collision before it has a chance to equilibrate. We have considered [Formula: see text] collision with a center-of-mass energy of 200 GeV. We use the nonextensive Tsallis statistics to find the entropic index in the partonic stages of the relativistic heavy ion collisions. We find that the temperature and the entropic index have a linear relationship during the partonic stages of the heavy ion collision. This has already been observed in the hadronic phase. A detailed analysis of the dependence of the entropic index on the system shows that for increasing spacetime rapidity, the entropic index of the partonic system increases. The entropic index also depends on the beam collision energy. The calculation of the entropic index from the experimental data fitting of the transverse momenta deals with the hadronic phase. However, our study shows that the behavior of the entropic index in the initial nonequilibrium stage of the collision is very similar to the behavior of the entropic index in the hadronic stage.


2019 ◽  
Vol 204 ◽  
pp. 07002 ◽  
Author(s):  
Alexander Ivashkin ◽  
Dmitry Finogeev ◽  
Marina Golubeva ◽  
Fedor Guber ◽  
Alexander Izvestnyy ◽  
...  

The main purpose of the FHCal is to provide an experimental measurement of a heavy-ion collision centrality (impact parameter) and orientation of its reaction plane. FHCal consists of two identical arms placed at the left/right sides from the beam collision point. Due to the fine modular structure and detection of spectators in both forward/backward regions, the angular resolution of the reaction plane reconstruction is below 30 degrees. Since the heavy fragments escape into beam holes, it is not possible to distinguish the central and peripheral collisions using only the deposited energies in FHCal. The subdivision of the calorimeter into two, inner and outer parts, and the calculation of the energy depositions separately in these calorimeter parts allow one to construct a new observable, the energy asymmetry. Taking the two-dimensional correlation between the energy asymmetry and full energy deposition in the calorimeter, it would be possible to resolve the ambiguity in the centrality determination.


2018 ◽  
Vol 175 ◽  
pp. 07036
Author(s):  
Jana N. Guenther ◽  
Szabolcs Borsányi ◽  
Zoltan Fodor ◽  
Sandor D. Katz ◽  
Attila Pásztor ◽  
...  

When comparing lattice calculation to experimental data from heavy ion collision experiments, the higher order fluctuations of conserved charges are important observables. An efficient way to study these fluctuations is to determine them from simulations at imaginary chemical potential. In this talk we present results up to the six order derivative in μB (with up to eighth order included in the fit), calculated on a 483 × 12 lattice with staggered fermions using different values of μB while μS = μQ = 0.


2016 ◽  
Vol 25 (02) ◽  
pp. 1650011
Author(s):  
A. Strazzeri ◽  
A. Italiano

A closed-form theoretical approach describing in a single picture both the evaporation component and the fast nonequilibrium component of the sequential fission of projectile-like fragments in a peripheral heavy-ion collision is derived and then applied to the dynamical fission observed in the [Formula: see text]+[Formula: see text] semiperipheral collision at 35A[Formula: see text]MeV. Information on the reaction mechanism is obtained such as the opposite polarization effects and the estimate of the “formation-to-fast fission lifetimes” of the fissioning fragment.


2004 ◽  
Vol 19 (09) ◽  
pp. 1453-1474 ◽  
Author(s):  
B. MOHANTY ◽  
T. K. NAYAK ◽  
Y. P. VIYOGI ◽  
D. P. MAHAPATRA

The experimental observation of disoriented chiral condensate is affected due to various physical and detector related effects. We study and quantify the strength of the experimental signal, "neutral pion fraction" within the framework of a simple DCC model, using the analysis methods based on the multi-resolution discrete wavelet technique and by evaluating the signal to background ratio. The scope and limitations of DCC search in heavy-ion collision experiments using various combination of detector systems are investigated.


2018 ◽  
Vol 171 ◽  
pp. 08002
Author(s):  
Stefan Schramm ◽  
Veronica Dexheimer ◽  
Ayon Mukherjee ◽  
Jan Steinheimer

We discuss the effect of exotic particles in neutron star matter and the corresponding impact on gross properties of neutron stars within effective models for the strong interaction. Particularly, for the quark-hadron parity-doublet model, we show results for compact star properties and discuss the phase structure of the model and its possible relevance for heavy-ion collision phenomenology.


1991 ◽  
Vol 06 (15) ◽  
pp. 2569-2581 ◽  
Author(s):  
M. JACOB

This review is the full version of an invited contribution to the session on heavy-ion collisions at the Singapore Conference, where several topical points were discussed in detail, through a series of talks.


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