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![Variations of the longitudinal flow velocities with respect to . Open circles are the results of [27].](profile/Prashant-Srivastava-18/publication/221665848/figure/fig5/AS:11431281307883443@1738719186954/Variations-of-the-longitudinal-flow-velocities-with-respect-to-Open-circles-are-the.jpg)
Variations of the longitudinal flow velocities with respect to . Open circles are the results of [27].
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Recently, we proposed a thermodynamically consistent excluded-volume model for the HG fireball and we noticed that our model gives a suitable description of various properties of multiparticle production and their ratios in the entire range of temperatures and baryon densities. Our aim in this paper is to obtain the variations of freeze-out volume...
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Citations
... Recently we have proposed [24][25][26][27][28] a thermodynamically consistent excluded volume model for the hot and dense hadron gas (HG). In this model, the grand canonical partition function for the HG with full quantum statistics and after suitably incorporating excluded volume correction is [24][25][26][27][28] ...
... Recently we have proposed [24][25][26][27][28] a thermodynamically consistent excluded volume model for the hot and dense hadron gas (HG). In this model, the grand canonical partition function for the HG with full quantum statistics and after suitably incorporating excluded volume correction is [24][25][26][27][28] ...
... Figure 2 presents the variation of total multiplicity of + with respect to √ . In the CBM energy range, the fireball volume at freeze-out, extracted in the excluded volume model approach, appears almost constant [28] for all emitted particles. We have taken 5000 fm 3 as the fireball volume in order to calculate the total multiplicity of hadrons. ...
The compressed baryonic matter (CBM) experiment planned at the Facility for Antiproton
and Ion Research (FAIR) will provide a major scientific effort for exploring the properties
of strongly interacting matter in the high baryon density regime. One of the important
goals behind such experiment is to precisely determine the equation of state (EOS) for the
strongly interacting matter at extremely large baryon density. In this paper, we have used
some successful models for RHIC and LHC energies to predict different particle ratios and
the total multiplicity of various hadrons in the CBM energy range, that is, from 10 A GeV to
40 A GeV lab energies, which corresponds to 4.43 A GeV and 8.71 A GeV center-of-mass
energies. Our main emphasis is to estimate the strange particles enhancement as well as an
increase in the net baryon density at CBM experiment. We have also compared the model
results with the experimental data obtained at alternating gradient synchrotron (AGS) and
super proton synchrotron (SPS).
... The production of strange particles in heavy-ion collisions is considered as one of the most important signals for the phase transition from hot, dense hadron gas (HG) to quark-gluon plasma (QGP) [1]. Recently we have analyzed the production of strange hadrons over a broad energy range from AGS to LHC energies using our new thermodynamically consistent excludedvolume model [2]. We have suitably incorporated the attractive interactions between hadrons through the addition of hadron resonances in our model. ...
... We assign an equal hard-core radius to each baryon in order to include repulsive interactions between them while mesons in the model are treated as pointlike particles. Using chemical freeze-out criteria as proposed by us [2], we calculate strange and non-strange hadron ratios and compare our results with the experimental data. We also study the production of light nuclei, hypernuclei and their antinuclei from AGS to LHC energies using our model and confront our model predictions with the experimental results. ...
... The grand canonical partition function for baryons in our thermodynamically consistent excluded-volume model can be written as follows [2, 3] : ...
We present a systematic study of production of strange and non-strange hadron
yields and their ratios obtained in various experiments using our
thermodynamically consistent excluded-volume model. We also analyze the
production of light nuclei, hypernuclei and their antinuclei in terms of our
excluded-volume model over a broad energy range starting from Alternating
Gradient Synchrotron (AGS) to Large Hadron Collider (LHC) energies. Further, we
extend our model for studying rapidity spectra of hadrons produced in heavy-ion
collisions.
... We calculate various thermodynamical quantities like number density etc. of HG and compare our model results with that of URASiMA event generator [4]. We use our freeze-out picture [5] for calculating various hadron ratios and compare our results with the experimental data and various excludedvolume models. In order to make the discussion complete, we further derive η/s etc. from our model and compare them with other models. ...
... Recently, we have proposed a thermodynamically consistent excluded-volume model for a hot, dense HG [2, 3, 5]. The attractive interaction between baryons and mesons is realized by including the baryon and meson resonances in our model calculation. ...
... We find that [8]. Symbols are the experimental data [5]. RHIC data are at mid-rapidity. ...
We formulate a thermodynamically consistent equation of state (EOS), based on
excluded-volume approach, for a hot, dense hadron gas (HG). We calculate
various thermodynamical quantities of HG and various hadron ratios and compare
our model results with the results of other excluded-volume models and
experimental data. We also calculate various transport coefficients such as
etc. and compare them with other HG model results. Furthermore, we
test the validity of our model in getting the rapidity spectra of various
hadrons and the effect of flow on them is investigated by matching our
predictions with the experimental data.
... In this section, we study the rapidity and transverse mass spectra of hadrons using thermal approach. We can rewrite (36) in the following manner [58]: ...
... However, we measure all these quantities precisely at the chemical freeze-out using our model, and hence quantitatively we do not require any normalizing factor as required in [164]. We use the following expression to calculate the rapidity distributions of baryons in the thermal model [58]: ...
... However, (64) describes the experimental data only at midrapidity, while it fails at forward and backward rapidities, so we need to modify it by incorporating a flow factor in the longitudinal direction. Thus the resulting rapidity spectra of ith hadron is [37,38,58,164] ...
The current status of various thermal and statistical descriptions of particle production in the ultrarelativistic heavy-ion collisions experiments is presented in detail. We discuss the formulation of various types of thermal models of a hot and dense hadron gas (HG) and the methods incorporated in the implementing of the interactions between hadrons. It includes our new excluded-volume model which is thermodynamically consistent. The results of the above models together with the experimental results for various ratios of the produced hadrons are compared. We derive some new universal conditions emerging at the chemical freeze-out of HG fireball showing independence with respect to the energy as well as the structure of the nuclei used in the collision. Further, we calculate various transport properties of HG such as the ratio of shear viscosity-to-entropy using our thermal model and compare with the results of other models. We also show the rapidity as well as transverse mass spectra of various hadrons in the thermal HG model in order to outline the presence of flow in the fluid formed in the collision. The purpose of this review article is to organize and summarize the experimental data obtained in various experiments with heavy-ion collisions and then to examine and analyze them using thermal models so that a firm conclusion regarding the formation of quark-gluon plasma (QGP) can be obtained.
The multiplicity per rapidity of the well-identified particles , , , , , p, and measured in different high-energy experiments, at energies ranging from 6.3 to 5500 GeV, is successfully compared with the Cosmic Ray Monte Carlo event generator. For these rapidity distributions, we introduce a theoretical approach based on fluctuations and correlations (Carruthers approach) and another one based on statistical thermal assumptions (hadron resonance gas approach). Both approaches are fitted to both sets of results deduced from experiments and simulations. We found that the Carruthers approach reproduces well the full range of multiplicity per rapidity for all produced particles, at the various energies, while the HRG approach fairly describes the results within a narrower rapidity range. While the Carruthers approach seems to match well with the Gaussian normal distribution, ingredients such as flow and interactions should be first incorporated in the HRG approach. We conclude that fluctuations, correlations, interactions, and flow, especially in the final state, assure that the produced particles become isotropically distributed.
The ratio of (pseudo)rapidity density of transverse energy and the (pseudo)rapidity density of charged particles, which is a measure of the mean transverse energy per particle, is an important observable in high energy heavy-ion collisions, which reveals about the mechanism of particle production and the freeze-out criteria. Its collision energy and centrality dependence is exactly like the chemical freeze-out temperature till top RHIC energy. The LHC measurement at = 2.76 TeV brings up new challenges to rule out the mechanisms of gluon saturation or non-equilibrium phenomena being prevalent at high energies, which could contribute to the above observable. The Statistical Hadron Gas Model (SHGM) with a static fireball approximation has been successful in describing both the centrality and energy dependence till top RHIC energies. However, the SHGM predictions for higher energies are highly underestimated by the LHC data. In order to understand this, we have incorporated radial flow effect in an excluded volume SHGM. The hard-core radius of baryons at lower collision energies plays an important role in the description of a hadronic system. In view of this, in order to make a complete energy dependence study from FAIR to LHC energies, we have considered the excluded volume SHGM. Our studies suggest that the collective flow plays an important role in describing and it could be one of the possible parameters to explain the jump observed in from RHIC to LHC energies.
Single particle transverse mass spectra and HBT radii of identical pion and identical kaon are analyzed with a blast-wave parametrization under the assumptions of local thermal equilibrium and transverse expansion. Under the assumptions, temperature parameter T and transverse expansion rapidity ρ are sensitive to the shapes of transverse mass mT spectrum and HBT radius Rs(KT). Negative and positive correlations between T and ρ are observed by fitting mT spectrum and HBT radius Rs(KT), respectively. For a Monte Carlo simulation using the blast-wave function, T and ρ are extracted by fitting mT spectra and HBT radii together utilizing a combined optimization function χ2. With this method, T and ρ of the Monte Carlo sources can be extracted. Using this method for A Multi-Phase Transport (AMPT) model at Relativistic Heavy Ion Collider (RHIC) energy, the differences of T and ρ between pion and kaon are observed obviously, and the tendencies of T and ρ versus collision energy sNN are similar with the results extracted directly from the AMPT model.
The property of limiting fragmentation of various observables such as rapidity distributions (dN/dy), elliptic flow (), average transverse momentum () etc. of charged particles is observed when they are plotted as a function of rapidity (y) shifted by the beam rapidity () for a wide range of energies from AGS to RHIC. Various theoretical methods have been used to study the phenomenon of limiting fragmentation. Earlier, it has been shown that the thermal model fails to explain the limiting fragmentation phenomenon for pion rapidity spectra at LHC energies. Since there is no experimental data of pion rapidity density at forward rapidities at LHC energies, hence one can not test experimentally whether limiting fragmentation occurs at this energy. So, it is very interesting to verify this phenomenon of limiting fragmentation theoretically at LHC energies. We study such a phenomenon for pion rapidity spectra using our thermal model with the effect of flow. Our finding advocates the observation of extended longitudinal scaling in the rapidity spectra of pions from AGS to lower to top RHIC energy, while it is observed to be violated at top RHIC and LHC energies.
The new excluded-volume hadron gas model by Singh et al. is critically discussed. We demonstrate that in this model the results obtained from relations between thermodynamical quantities disagree with the corresponding results obtained by statistical ensemble averaging. Thus, the model does not satisfy the requirements of thermodynamical consistency.
The current status of various thermal and statistical descriptions of
particle production in the ultra-relativistic heavy-ion collisions experiments
is presented in detail. We discuss the formulation of various types of thermal
models of a hot and dense hadron gas (HG) and the methods incorporated in
implementing the interactions between hadrons. We first obtain the
parameterization of center-of-mass energy () in terms of
temperature (T) and baryon chemical potential () obtained by analyzing
the particle ratios at the freeze-out over a broad energy range from the lowest
Alternating Gradient Synchrotron (AGS) energy to the highest Relativistic
Heavy-Ion Collider (RHIC) energies. The results of various thermal models
together with the experimental results for the various ratios of yields of
produced hadrons are then compared. We have derived some new universal
conditions emerging at the chemical freeze-out of HG fireball which demonstrate
the independence with respect to the energy as well as the structure of the
nuclei used in the collision. Further, we perform the calculation of various
transport properties of HG such as shear viscosity-to-entropy density ratio
() etc. using thermal model and compare with the results of other
models. We also present the calculation of the rapidity as well as transverse
mass spectra of various hadrons in the thermal HG model. The purpose of this
review article is to organize and summarize the experimental data obtained in
various experiments with heavy-ion collisions and then to examine and analyze
them using thermal models so that a firm conclusion regarding the formation of
quark-gluon plasma (QGP) can be obtained.
