Melting hadrons, boiling quarks

The kurtosis and skewness of net baryon-number fluctuations are studied for the magnetized phase diagram of three-flavor quark matter within the Polyakov extended Nambu-Jona-Lasinio model. Two models with magnetic catalysis and inverse magnetic catalysis are considered. Special attention is given to their behavior in the neighborhood of the light and strange critical end points (CEPs). Several isentropic trajectories that come close the CEPs are studied in order to analyze possible signatures of a CEP in the presence of external magnetic fields. The effect of the magnetic field on the velocity of sound, v 2 s , when both the light and strange CEPs are approached from the crossover region is also investigated by calculating their temperature and baryon chemical potential dependencies at fixed distances from these CEPs. Regions with large fluctuations but no CEP in nonmagnetized matter develop a CEP under the action of a strong magnetic field. Besides, the Landau quantization of the quark trajectories may result in the appearance of extra CEPs, in particular, in the strange sector for strong magnetic fields, identifiable by the net baryon-number fluctuations. Stiffer (smoother) fluctuations in the region of the CEP are characteristic of models that do not predict (do predict) the inverse magnetic catalysis at zero chemical potential. Particularly interesting is the ratio χ 4 B /χ 2 B that has a more pronounced peak structure, indicating that it is eventually a more convenient probe for the search of a CEP. The speed of sound shows a much richer structure in magnetized quark matter and allows one to identify both chiral and deconfinement transitions.

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“…The sound velocity, v 2 s = ∂P/∂E, is a fundamental quantity in the expansion of hot and dense matter [68].…”

Section: Resultsmentioning

confidence: 99%

Net baryon-number fluctuations in magnetized quark matter

2018

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“…It allows for a non-equilibrium chemical potential 2 for each particle, due to partial equilibration of the constituent quarks in the fast expanding fireball [33,34]. This model has two more parameters compared to the standard TM -one for light and one for strange quarks.…”

Section: Introductionmentioning

confidence: 99%

Fluctuations as a test of chemical nonequilibrium at energies available at the CERN Large Hadron Collider

Begun

2016

Phys. Rev. C

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It is shown that large chemical potential leads to the significant increase of multiplicity fluctuations for bosons, and makes the fluctuations infinite in the case of Bose-Einstein condensation. It allows to distinguish between the models that explain the anomalous proton to pion ratio and the low transverse momentum enhancement of pion spectra in Pb+Pb collisions at the LHC within chemical equilibrium or non-equilibrium models. The effects of resonance decays, finite size of the system, requirements to the event statistics, different momentum cuts, and limited detector acceptance are considered. The obtained results show the possibility to observe a substantial increase of the normalized kurtosis for positively or negatively charged pions in the case of non-equilibrium or partial pion condensation using currently measured data.

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“…An incomplete equilibration of the strange hadrons and a finite detector acceptance should be taken into account.Many previous fits of the hadron multiplicity data within the HRG model, both in the GCE and CE, demonstrated an incomplete chemical equilibration of the strange hadrons. This is usually compensated by the strangeness suppression parameter γ S[31][32][33]36] with numerical values in the range of 0.5 < γ S < 1 for the SPS energies. The number of strange and antistrange particles becomes then smaller than that expected in the equilibrium HRG.…”

mentioning

confidence: 99%

Hadron yields and fluctuations at energies available at the CERN Super Proton Synchrotron: System-size dependence from Pb + Pb to p+p collisions

et al. 2019

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The kaon to pion ratio K + /π + and the scaled variance ω − for fluctuations of negatively charged particles are studied within the statistical hadron resonance gas (HRG) model and the Ultra relativistic Quantum Molecular Dynamics (UrQMD) transport model. The calculations are done for p+p, Be+Be, Ar+Sc, and Pb+Pb collisions at the CERN Super Proton Synchrotron energy range to reveal the system size dependence of hadron production. For the HRG calculations the canonical ensemble is imposed for all conserved charges. In the UrQMD simulations the centrality selection in nucleus-nucleus collisions is done by calculating the forward energy EF deposited in the Projectile Spectator Detector, and the acceptance maps of the NA61/SHINE detectors are used. A comparison of the HRG and UrQMD results with the data of the NA61/SHINE Collaboration is done. To understand a difference of the event-by-event fluctuations in p+p and heavy ion collisions the centrality selection procedure in the sample of all inelastic p+p events is proposed and analyzed within the UrQMD simulations.

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Melting hadrons, boiling quarks

Cited by 49 publications

References 187 publications

Net baryon-number fluctuations in magnetized quark matter

Net baryon-number fluctuations in magnetized quark matter

Fluctuations as a test of chemical nonequilibrium at energies available at the CERN Large Hadron Collider

Hadron yields and fluctuations at energies available at the CERN Super Proton Synchrotron: System-size dependence from Pb + Pb to p+p collisions

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