arXiv subjects

Dariusz Prorok

Publications and source records attributed to Dariusz Prorok.

At least 19 recordsLinked to original sources

arXiv2021

Influence of correlations between yields on the chemical freeze-out temperature

A statistical (thermal) model is applied to the description of hadron yields measured at central nucleus-nucleus collisions at the top RHIC energy $\sqrt{s_{NN}} = 200$ GeV and the LHC energy $\sqrt{s_{NN}} = 2.76$ TeV. In contrast to the previous analyzes a more general form of the least squares test statistic is used, which takes into account also possible correlations between different species of yields. In addition to hadrons also light nuclei are included in the fits. Because of the lack of data, a toy model is constructed where the correlation coefficients are just free parameters. Because of this the presented considerations are speculative and should be treated as an imperfect illustration of the problem. Within these limitations it is impossible to formulate any definite conclusion, it might be only mentioned that for the considered examples the dependence of the freeze-out temperature and baryon chemical potential on correlations turned out to be weak.

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arXiv2019

Centrality dependence of freeze-out temperature fluctuations in Pb-Pb collisions at the LHC

Many data in the High Energy Physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the whole spectra of pions, kaons and protons measured at midrapidity in Pb-Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV can be fitted simultaneously. The invariant distributions are predicted with the help of the single-freeze-out model in the chemical equilibrium framework. The method is applied to the measurements in centrality bins of Pb-Pb collisions and gives acceptable fits for all but peripheral bins. The comparison with the results obtained in the framework of the original single-freeze-out model is also presented. Some more general, possible implications of this approach are pointed out.

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arXiv2016

Single Freeze-Out, Statistics and Pion, Kaon and Proton Production in Central Pb-Pb Collisions at $\sqrt{s_{NN}} = 2.76$ TeV

Many data in the high energy physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the acceptable fit to the whole spectra of pions, kaons and protons measured at midrapidity in central Pb-Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV [Phys.Rev.Lett.109,252301(2012)] is obtained. The invariant distributions are predicted with the help of the single-freeze-out model in the chemical equilibrium framework. Low $p_{T}$ pions and protons are reproduced simultaneously as well as $p/π$ ratio. Additionally, correct predictions extend over lower parts of large $p_{T}$ data. Some more general, possible implications of this approach are pointed out.

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arXiv2013

Multiplicities in Au-Au and Cu-Cu collisions at \sqrt{s_{NN}} = 62.4 and 200 GeV

Likelihood ratio tests are performed for the hypothesis that charged-particle multiplicities measured in Au-Au and Cu-Cu collisions at $\sqrt{s_{NN}} = 62.4$ and 200 GeV are distributed according to the negative binomial form. Results suggest that the hypothesis should be rejected in the all classes of collision systems and centralities of PHENIX-RHIC measurements. However, the application of the least-squares test statistic with systematic errors included shows that for the collision system Au-Au at $\sqrt{s_{NN}} = 62.4$ GeV the hypothesis could not be rejected in general.

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arXiv2011

Multiplicities in ultrarelativistic proton-(anti)proton collisions and negative binomial distribution fits

Likelihood ratio tests are performed for the hypothesis that charged-particle multiplicities measured in proton-(anti)proton collisions at $\sqrt{s}$ = 0.9 and 2.36 TeV are distributed according to the negative binomial form. Results indicate that the hypothesis should be rejected in the all cases of ALICE-LHC measurements in the limited pseudo-rapidity windows, whereas should be accepted in the corresponding cases of UA5 data. Possible explanations of that and of the disagreement with the least-squares fitting method are given.

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arXiv2010

Thermal freeze-out versus chemical freeze-out reexamined

An alternative, to the commonly used blast-wave, model describing the freeze-out hypersurface is applied to fit the $p_{T}$-spectra of identified hadrons measured at relativistic heavy-ion collisions at $\sqrt{s_{NN}}=62.4, 130$ and 200 GeV. Decays of resonances are taken into account completely. It has turned out that the fitted freeze-out temperature and baryon number chemical potential depend weakly on the centrality of the collision and their values are close to the chemical freeze-out values determined from fits to particle yield ratios.

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arXiv2008

J/$ψ$ absorption in a multicomponent hadron gas

A model for anomalous $J/Ψ$ suppression in high energy heavy ion collisions is presented. As the additional suppression mechanism beyond standard nuclear absorption inelastic $J/Ψ$ scattering with hadronic matter is considered. Hadronic matter is modeled as an evolving multi-component gas of point-like non-interacting particles (MCHG). Estimates for the sound velocity of the MCHG are given and the equation of state is compared with Lattice QCD data in the vicinity of the deconfinement phase transition. The approximate cooling pattern caused by longitudinal expansion is presented. It is shown that under these conditions the resulting $J/Ψ$ suppression pattern agrees well with NA38 and NA50 data.

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arXiv2006

The statistical hadronization model approach to $\sqrt{s_{NN}}=200$ GeV Au-Au collisions: $p_{T}$-spectra fits and global variable predictions

Three possible scenarios of the statistical hadronization model are reexamined with the use of the $p_{T}$ spectra of the PHENIX and very low $p_{T}$ PHOBOS measurements at $\sqrt{s_{NN}}=200$ GeV. These scenarios are: (\textit{a}) full chemical non-equilibrium, (\textit{b}) strangeness chemical non-equilibrium and (\textit{c}) chemical equilibrium. Fits to the spectra are done within the Cracow single-freeze-out model, which takes into account both the expansion and resonance decays. Predictions for spectra of $ϕ$, $K(892)^{\ast 0}$ and $π^{0}$ are also given. The global variables like the transverse energy at midrapidity, the charged particle multiplicity at midrapidity and the total multiplicity of charged particles are evaluated and their predicted values agree qualitatively well with the experimental data. The thorough analysis within this model suggests that the chemical full non-equilibrium case is the least likely and both other cases are of the similar likelihood. It is also shown that if the full chemical non-equilibrium freeze-out took place it could manifest itself in the enhancement of the $π^{0}$-production at very low transverse momenta.

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arXiv2006

Global variables for various centralities at RHIC: a Cracow model approach

The final $p_{T}$-spectra measured at RHIC at $\sqrt{s_{NN}}=130$ and 200 GeV are fitted within the Cracow single-freeze-out model. Then the global variables like the transverse energy at midrapidity, the charged particle multiplicity at midrapidity and the total multiplicity of charged particles are evaluated. The predictions agree fairly well with the experimental data. The centrality independence of the total number of charged particles per participant pair has been also reproduced.

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arXiv2006

Centrality dependence of global variables in relativistic heavy ion collisions: Final $p_{T}$ data analysis in the framework of a statistical model

The global variables like the transverse energy at midrapidity, the charged particle multiplicity at midrapidity and the total multiplicity of charged particles are evaluated in the single-freeze-out statistical model for different centrality bins at RHIC at $\sqrt{s_{NN}}=130$ and 200 GeV. Full description of decays of hadron resonances is applied in these estimations. The geometric parameters of the model are obtained from the fit to the final data on the $p_{T}$ spectra. The predicted values of the global variables agree qualitatively well with the experimental data. The centrality independence of the total number of charged particles per participant pair has been also reproduced.

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arXiv2005

The centrality dependence of transverse energy and charged particle multiplicity at RHIC: Statistical model analysis

The transverse energy and charged particle multiplicity at midrapidity and their ratio are evaluated in a statistical model with the longitudinal and transverse flows for different centrality bins at RHIC at $\sqrt{s_{NN}}=130$ and 200 GeV. Full description of decays of hadron resonances is applied in these estimations. The predictions of the model at the freeze-out parameters, which were determined independently from measured particle yields and $p_{T}$ spectra, agree qualitatively well with the experimental data. The observed overestimation of the ratio can be explained for more central collisions by the redefinition of $dN_{ch}/dη|_{mid}$.

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arXiv2005

Transverse energy and charged particle multiplicity at various centralities at RHIC: Statistical model estimates

The transverse energy and the charged particle multiplicity at midrapidity are evaluated in a single-freeze-out model for different centrality bins at RHIC at $\sqrt{s_{NN}}=130$ and 200 GeV. The predictions of the model are done at the freeze-out parameters determined earlier from measured particle yields and $p_{T}$ spectra. The results agree qualitatively well with the experimental data.

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arXiv2005

Transverse energy per charged particle at relativistic energies from a statistical model with expansion

Transverse energy and charged particle pseudorapidity densities at midrapidity and their ratio, $dE_{T}/dη\mid_{mid} / dN_{ch}/dη|_{mid}$, are evaluated in a statistical model with longitudinal and transverse flows for the wide range of colliders, from AGS to RHIC at $\sqrt{s_{NN}}=200$ GeV. Evaluations are done at freeze-out parameters established independently from fits to observed particle yields and $p_{T}$ spectra. Decays of hadron resonances are treated thoroughly and are included in derivations of $dE_{T}/dη|_{mid}$ and $dN_{ch}/dη|_{mid}$. The predictions of the model agree well with the experimental data. However, some (explicable) overestimation of the ratio has been observed.

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arXiv2004

The transverse energy and the charged particle multiplicity in a statistical model with expansion

Global variables such as the transverse energy and the charged particle multiplicity and their ratio are evaluated, in a statistical model with expansion, for heavy-ion collisions from AGS to RHIC at $\sqrt{s_{NN}}=200$ GeV. Full description of decays of hadron resonances is applied. The predictions of the model done at the freeze-out parameters established independently from observed particle yields and $p_{T}$ spectra agree well with the experimental data. However, some (explicable) overestimation of the ratio has been found.

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arXiv2004

The transverse energy per charged particle estimates in the framework of a statistical model

The transverse energies and the charged particle multiplicities at midrapidity as well as their ratio, $dE_{T}/dη\mid_{mid} / dN_{ch}/dη|_{mid}$, are evaluated in a statistical model with expansion for the wide range of heavy-ion collisions, from AGS to RHIC at $\sqrt{s_{NN}}=200$ GeV. Full description of decays of hadron resonances is applied in calculations of both $dE_{T}/dη|_{mid}$ and $dN_{ch}/dη|_{mid}$. The predictions of the model at the freeze-out parameters, established independently from observed particle yields and $p_{T}$ spectra, agree well with the experimental data.

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arXiv2002

J/Ψsuppression in an equilibrium hadron gas

A model for $J/Ψ$ suppression at a high energy heavy ion collision is presented. The main (and the only) reason for the suppression is $J/Ψ$ inelastic scattering within hadron matter. The hadron matter is in the form of an evolving multi-component point-like non-interacting gas. The estimations of the sound velocity in the gas and the approximate pattern of cooling caused by the longitudinal expansion are also presented. It is shown that under such circumstances and with $J/Ψ$ disintegration in nuclear matter added, $J/Ψ$ suppression evaluated agrees well with NA38 and NA50 data. Additionally, some rough estimations of $J/Ψ$ suppression in hadron matter described in the framework of the excluded volume gas model are given.

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arXiv2001

$J/Ψ$ suppression in an expanding hadron gas

A model for $J/Ψ$ suppression at a high energy heavy ion collision is presented. The main (and the only) reason for the suppression is $J/Ψ$ inelastic scattering within hadron matter. The hadron matter is in the form of a multi-component non-interacting gas. Also the evolution of the gas, both longitudinal and transverse, is taken into account. It is shown that under such circumstances and with $J/Ψ$ disintegration in nuclear matter added, $J/Ψ$ suppression evaluated agrees well with NA38 and NA50 data.

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arXiv2001

J/Psi suppression in colliding nuclei: statistical model analysis

We consider the $J/Ψ$ suppression at a high energy heavy ion collision. An ideal gas of massive hadrons in thermal and chemical equilibrium is formed in the central region. The finite-size gas expands longitudinally in accordance with Bjorken law. The transverse expansion in a form of the rarefaction wave is taken into account. We show that $J/Ψ$ suppression in such an environment, when combined with the disintegration in nuclear matter, gives correct evaluation of NA38 and NA50 data in a broad range of initial energy densities.

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