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Title Hybrid model with viscous relativistic hydrodynamics: a role of constraints on the shear-stress tensor Author info A. S. Khvorostukhin ... [et al.] Author Khvorostukhin A. S. (34%)
Co-authors Kolomeitsev Evgeni E. 1970- (33%) UMBFP06 - Katedra fyziky
Toneev V. D. (33%)
Source document The European Physical Journal A : Hadrons and Nuclei. Vol. 57, no. 10 (2021), pp. 294-1-294-25. - New York : Springer Nature, 2021 Keywords relativistic hydrodynamics heavy ion collisions viscosity Form. Descr. články - journal articles Language English Country Germany Annotation We present the hybrid model connecting the parton–hadron–string dynamic model (PHSD) and a hydrodynamic model taking into account shear viscosity within the Israel–Stewart approach. The numerical scheme, initialization, and particlization procedure are discussed in detail. The performance of the code is tested on the pion and proton rapidity and transverse mass distributions calculated for Au + Au and Pb+Pb collisions at AGS–SPS energies. The influence of the switch time from transport to hydro models, the viscous parameter, and freeze-out time are discussed. Since the applicability of the Israel–Stewart hydrodynamics assumes the perturbative character of the viscous stress tensor, πμν, which should not exceed the ideal energy–momentum tensor, T μν id , hydrodynamical codes usually rescale the shear stress tensor if the inequality πμν T μν id is not fulfilled in some sense. There are several conditions used in the literature and we analyze in detail the influence of different conditions and values of the cut-off parameter on observables.We show that the form of the corresponding condition plays an important role in the sensitivity of hydrodynamic calculations to the viscous parameter – a ratio of the shear viscosity to the entropy density, η/s. It is shown that the constraints used in the vHLLE and MUSIC models give the same results for the observables.With these constraints, the rapidity distributions and transverse momentum spectra are most sensitive to a change of the η/s ratio. We demonstrate that these constraints do not guarantee that each element of the πμν tensor is smaller than the corresponding element T μν id . As an alternative, a strict condition is used. When applied it reduces the sensitivity of the proton and pion momentum distributions to the viscosity parameter. We performed global fits of the rapidity and transverse mass distributions of pion and protons. It was also found that η/s as a function of the collision energy monotonically increases from Elab = 6 AGeV up to Elab = 40 AGeV and saturates for higher SPS energies. We observe that it is difficult to reproduce simultaneously pion and proton rapidity distribution within our model with the present choice of the equation of state without a phase transition. URL Link na plný text Public work category ADC No. of Archival Copy 50708 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika 
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Title Vorticity and hyperon polarization at energies available at JINR Nuclotron-based Ion Collider fAcility Author info E. E. Kolomeitsev, V. D. Toneev ... [et al.] Author Kolomeitsev Evgeni E. 1970- (34%) UMBFP06 - Katedra fyziky
Co-authors Toneev V. D. (33%)
Voronyuk Vadym (33%)
Source document Physical Review C. Vol. 97, no. 6 (2018), pp. [1-9]. - Maryland : American Physical Society, 2018 Keywords heavy ion collisions vorticity hyperon polarization Language English Country United States of America systematics 53 Annotation We study the formation of fluid vorticity and the hyperon polarization in heavy-ion collisions at energies available at the JINR Nuclotron-based Ion Collider fAcility in the framework of the parton-hadron-string dynamic model, taking into account both hadronic and quark-gluonic (partonic) degrees of freedom. The vorticity properties in peripheral Au+Au collisions at √sNN= 7.7 GeV are demonstrated and confronted with other models. The obtained result for the Lambda polarization is in agreement with the experimental data by the STAR Collaboration, whereas the model is not able to explain the observed high values of the antihyperon anti-Lambda polarization URL Link na plný text Public work category ADC No. of Archival Copy 43912 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika 
unrecognised
Title Directed flow in asymmetric nucleus-nucleus collisions and the inverse Landau-Pomeranchuk-Migdal effect Author info V. D. Toneev ... [et al.] Author Toneev V. D. (1%)
Co-authors Voronyuk Vadym (1%)
Kolomeitsev Evgeni E. 1970- (97%) UMBFP06 - Katedra fyziky
Cassing W. (1%)
Source document Physical Review C. Vol. 95, no. 3 (2017), pp. [1-6]. - Maryland : American Physical Society, 2017 Keywords heavy ion collisions energia - energy dense matter Language English Country United States of America systematics 53 Annotation It is proposed to identify a strong electric field-created during relativistic collisions of asymmetric nuclei-via the observation of pseudorapidity and transverse momentum distributions of hadrons with the same mass but opposite charge. The results of detailed calculations within the parton-hadron string dynamics (PHSD) approach for the charge-dependent directed flow v(1) are presented for semicentral Cu+Au collision at root S-NN = 200 GeV incorporating the inverse Landau-Pomeranchuk-Migdal (iLPM) effect, which accounts for a delay in the electromagnetic interaction with the charged degrees of freedom. By including the iLPM effect, we achieve a reasonable agreement of the PHSD results for the charge splitting in v(1)(p(T)) in line with the recent measurements by the STAR Collaboration for Cu+Au collisions at root s(NN) = 200 GeV while an instant appearance and coupling of electric charges at the hard collision vertex overestimates the splitting by about a factor of 10. We predict that the iLPM effect should practically disappear at energies of root s(NN) approximate to 9 GeV, which should lead to a significantly larger charge splitting of v1 at the future FAIR/NICA facilities. Public work category ADC No. of Archival Copy 39312 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika unrecognised
Title Lattice QCD constraints on hybrid and quark stars Author info Yu. B. Ivanov ... [et al.] Author Ivanov Yu. B. (16%)
Co-authors Khvorostukhin A. S. (16%)
Kolomeitsev Evgeni E. 1970- (16%)
Skokov V. V. (16%)
Toneev V. D. (16%)
Voskresensky Dmitri (20%)
Source document Physical Review C. Vol. 72, no. 2 (2005), pp. 5804-5804. - Maryland : American Physical Society, 2005 Keywords jadrová fyzika lattice QCD neutron stars hybrid stars Language English Country United States of America systematics 539.1 Annotation A QCD-motivated dynamical-quasiparticle model with parameters adjusted to reproduce the lattice-QCD equation of state is extrapolated from the region of high temperatures and moderate baryonic densities to the domain of high baryonic densities and zero temperature. The resulting equation of state matched with realistic hadronic equations of state predicts a phase transition into the quark phase at higher densities than those reachable in neutron star interiors. This excludes the possibility of the existence of hybrid (hadron-quark) stars. Pure quark stars are possible and have low masses, small radii, and very high central densities. Similar results are obtained for a simple bag model with massive quarks, fitted to reproduce the same lattice results. Self-bound quark matter is also excluded within these models. Uncertainties in the present extrapolation are discussed. Comparison with standard bag models is made Public work category ADC No. of Archival Copy 26413 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika unrecognised