Výsledky vyhľadávania
Title NICER data and a sigma-field-dependent stiffness of the hadronic equation of state Author info Evgeni Kolomeitsev, Dmitri Voskresensky Author Kolomeitsev Evgeni E. 1970- ( 50%) UMBFP06 - Katedra fyziky
Co-authors Voskresensky Dmitri (50%)
Source document Physical Review C. Vol. 110, no. 2 (2024), pp. 1-10. - Maryland : American Physical Society, 2024 Keywords neutrónové hviezdy nukleárna fyzika astrofyzika - astrophysics stavová rovnica Form. Descr. články - journal articles Language English Country United States of America Annotation Analyses for the NICER data indicate that there is no significant variation of compact star radii within the mass range of 1.4 to 2.0 solar masses. Yamamoto et al. [Phys. Rev. C 108, 035811 (2023)] concluded recently that “this feature cannot be reproduced by the hadronic matter due to the softening of the equation of state (EoS) by hyperon mixing, suggesting the possible existence of quark phases in neutron-star interiors.” Using a collection of 162 purely nucleonic, hyperonic, and quarkish EoSs from the CompOSE database and some other works, we verify that hyperons indeed lead to a significant difference in radii of stars of 1.4 and 2.0 solar masses, which diminishes in the presence of quarks. We compare the shapes of the mass-radius curves and show that hyperons and quarks in the neutron star cores prefer a particular curve shape with backbending. It is argued that the shape is controlled by the density dependence of the nuclear symmetry energy. We draw attention to the existence of a class of purely hadronic relativistic mean-field EoSs with scalar-field dependent hadron masses and coupling constants that satisfy the known constraints on the EoSs including the analyses of the new NICER data and the above requirement of insignificant variation of the neutron star radii. URL Link na zdrojový dokument Public work category ADC No. of Archival Copy 54690 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika 
článok
Title Helicity and vorticity in heavy-ion collisions at energies available at the JINR Nuclotron-based Ion Collider facility Author info N. S. Tsegelnik, E. E. Kolomeitsev, V. Voronyuk Author Tsegelnik Nikita S. (33%)
Co-authors Kolomeitsev Evgeni E. 1970- (34%) UMBFP06 - Katedra fyziky
Voronyuk Vadym (33%)
Source document Physical Review C. Vol. 107, no. 3 (2023), pp. 1-21. - Maryland : American Physical Society, 2023 Keywords ťažké ióny elektrónové urýchľovače helicita - helicity Form. Descr. články - journal articles Language English Country United States of America URL Link na plný text Public work category ADC No. of Archival Copy 54071 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika článok
Title Lambda and anti-Lambda Freeze-Out Distributions and Global Polarizations in Au+Au Collisions Par.title Λ and (Λ)over-bar Freeze-Out Distributions and Global Polarizations in Au plus Au Collisions Author info Nikita Tsegelnik, Evgeni Kolomeitsev, Vadym Voronyuk Author Tsegelnik Nikita S. (34%)
Co-authors Kolomeitsev Evgeni E. 1970- (33%) UMBFP06 - Katedra fyziky
Voronyuk Vadym (33%)
Source document Particles. Vol. 6, no. 1 (2023), pp. 373-384. - Basel : Multidisciplinary Digital Publishing Institute, 2023 Language English Country Switzerland URL Link na plný text Public work category ADM No. of Archival Copy 54073 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika článok
Title Kyvadlo, oscilácie a rezonancie Subtitle bakalárska práca Author info Mikhail Fedorov; školiteľ: Evgeni Kolomeitsev Author Fedorov Mikhail
Another authors Kolomeitsev Evgeni E. 1970- (Školiteľ (konzultant))
Corporation Univerzita Mateja Bela . Fakulta prírodných vied . Katedra fyziky , Banská Bystrica, Slovensko Issue data Banská Bystrica , 2022. - 50 s. Keywords fyzika - physics rezonancia - resonance kmity vynútené kmity Form. Descr. bakalárske práce - bachelor’s theses Language Slovak Country Slovak Republic systematics 53 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xk - Kvalifikačné práce Copy count 1, currently available 0, at library only 1 
kniha
Call number Location Sublocation Umiestnenie Info KP 61826 Univerzita Mateja Bela Universal reading room – deposit. Available in 2 days. In-Library Use Only Názov Hybrid model with viscous relativistic hydrodynamics: a role of constraints on the shear-stress tensor Aut.údaje A. S. Khvorostukhin ... [et al.] Autor Khvorostukhin A. S. (34%)
Spoluautori Kolomeitsev Evgeni E. 1970- (33%) UMBFP06 - Katedra fyziky
Toneev V. D. (33%)
Zdroj.dok. The European Physical Journal A : Hadrons and Nuclei. Vol. 57, no. 10 (2021), pp. 294-1-294-25. - New York : Springer Nature, 2021 Kľúč.slová relativistic hydrodynamics heavy ion collisions viscosity Form.deskr. články - journal articles Jazyk dok. angličtina Krajina Nemecko Anotácia 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 Kategória publikačnej činnosti ADC Číslo archívnej kópie 50708 Katal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Báza dát xpca - PUBLIKAČNÁ ČINNOSŤ Odkazy PERIODIKÁ-Súborný záznam periodika článok
Názov Charge and isospin fluctuations in a non-ideal pion gas with dynamically fixed particle number Aut.údaje Evgeni E. Kolomeitsev ... [et al.] Autor Kolomeitsev Evgeni E. 1970- (34%) UMBFP06 - Katedra fyziky
Spoluautori Voskresensky Dmitri (33%)
Borisov Maxim E. (33%)
Zdroj.dok. The European Physical Journal A : Hadrons and Nuclei. Vol. 57, no. 4 (2021), pp. [1-29]. - Berlin : Springer, 2021 Kľúč.slová Bose-Einsteinova kondenzácia - Bose-Einstein condensation heavy ion collisions Form.deskr. články - journal articles Jazyk dok. angličtina Krajina Nemecko Kategória publikačnej činnosti ADC Číslo archívnej kópie 49947 Katal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Báza dát xpca - PUBLIKAČNÁ ČINNOSŤ Odkazy PERIODIKÁ-Súborný záznam periodika článok
Názov On cooling of neutron stars with a stiff equation of state including hyperons Aut.údaje Hovik Grigorian, Evgeni E. Kolomeitsev ... [et al.] Autor Grigorian Hovik (25%)
Spoluautori Kolomeitsev Evgeni E. 1970- (25%) UMBFP06 - Katedra fyziky
Maslov Konstantin A. (25%)
Voskresensky Dmitri (25%)
Zdroj.dok. Universe. Vol. 4, no. 2 (2018), pp. 1-6. - Basel : Multidisciplinary Digital Publishing Institute, 2018 Kľúč.slová equation of state neutron stars neutrína - neutrinos Jazyk dok. angličtina Krajina Švajčiarsko Systematika 53 Anotácia Exploiting a stiff equation of state of the relativistic mean-field model MKVORHf with sigma-scaled hadron effective masses and couplings, including hyperons, we demonstrate that the existing neutron-star cooling data can be appropriately described within “the nuclear medium cooling scenario” under the assumption that different sources have different masses URL Link na zdrojový dokument Kategória publikačnej činnosti ADM Číslo archívnej kópie 43911 Katal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Báza dát xpca - PUBLIKAČNÁ ČINNOSŤ Odkazy PERIODIKÁ-Súborný záznam periodika 
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Názov Charged rho meson condensate in neutron stars within RMF models Aut.údaje Konstantin A. Maslov, Evgeni E. Kolomeitsev, Dmitry N. Voskresensky Autor Maslov Konstantin A. (34%)
Spoluautori Kolomeitsev Evgeni E. 1970- (33%) UMBFP06 - Katedra fyziky
Voskresensky Dmitri (33%)
Zdroj.dok. Universe. Vol. 4, no. 1 (2018), pp. 1-8. - Basel : Multidisciplinary Digital Publishing Institute, 2018 ; Compact stars in the QCD Phase Diagram medzinárodná konferencia Kľúč.slová neutron stars equation of state rho meson condensation maximum mass Delta resonances Jazyk dok. angličtina Krajina Švajčiarsko Systematika 53 Anotácia Knowledge of the equation of state (EoS) of cold and dense baryonic matter is essential for the description of properties of neutron stars (NSs). With an increase of the density, new baryon species can appear in NS matter, as well as various meson condensates. In previous works, we developed relativistic mean-field (RMF) models with hyperons and Δ -isobars, which passed the majority of known experimental constraints, including the existence of a 2 M ⊙ neutron star. In this contribution, we present results of the inclusion of ρ − -meson condensation into these models. We have shown that, in one class of the models (so-called KVOR-based models, in which the additional stiffening procedure is introduced in the isoscalar sector), the condensation gives only a small contribution to the EoS. In another class of the models (MKVOR-based models with additional stiffening in isovector sector), the condensation can lead to a first-order phase transition and a substantial decrease of the NS mass. Nevertheless, in all resulting models, the condensation does not spoil the description of the experimental constraints URL https://www.mdpi.com/2218-1997/4/1/1 Kategória publikačnej činnosti AFC Číslo archívnej kópie 43907 Katal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Báza dát xpca - PUBLIKAČNÁ ČINNOSŤ Odkazy PERIODIKÁ-Súborný záznam periodika nerozpoznaný
Názov Fluctuations in non-ideal pion gas with dynamically fixed particle number Aut.údaje E. E. Kolomeitsev, D. N. Voskresensky Autor Kolomeitsev Evgeni E. 1970- (50%) UMBFP06 - Katedra fyziky
Spoluautori Voskresensky Dmitri (50%)
Zdroj.dok. Nuclear Physics A. Vol. 973, (2018), pp. 89-103. - Amsterdam : Elsevier B.V., 2018 Kľúč.slová heavy ion collisions fluctuations Hartree approximation Bose-Einsteinova kondenzácia - Bose-Einstein condensation Jazyk dok. angličtina Krajina Holandsko Systematika 53 Anotácia We consider a non-ideal hot pion gas with the dynamically fixed number of particles in the model with the λφ4interaction. The effective Lagrangian for the description of such a system is obtained after dropping the terms responsible for the change of the total particle number. Reactions π+π−↔π0π0, which deter-mine the isospin balance of the medium, are permitted. Within the self-consistent Hartree approximation we compute the effective pion mass, thermodynamic characteristics of the system and the variance of the particle number at temperatures above the critical point of the induced Bose–Einstein condensation when the pion chemical potential reaches the value of the effective pion mass. We analyze conditions for the con-densate formation in the process of thermalization of an initially non-equilibrium pion gas. The normalized variance of the particle number increases with a temperature decrease but remains finite in the critical point of the Bose–Einstein condensation. This is due to the non-perturbative account of the interaction and is in contrast to the ideal-gas case. In the kinetic regime of the condensate formation the variance is shown to stay finite also URL Link na plný text Kategória publikačnej činnosti ADC Číslo archívnej kópie 43902 Katal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Báza dát xpca - PUBLIKAČNÁ ČINNOSŤ Odkazy PERIODIKÁ-Súborný záznam periodika nerozpoznaný
Názov Charged rho-meson condensation in neutron stars Aut.údaje Evgeni E. Kolomeitsev, K. A. Maslov ... [et al.] Autor Kolomeitsev Evgeni E. 1970- (34%) UMBFP06 - Katedra fyziky
Spoluautori Maslov K. A. (33%)
Voskresensky Dmitri (33%)
Zdroj.dok. Nuclear Physics A. Vol. 970, (2018), pp. 291-315. - Amsterdam : Elsevier B.V., 2018 Kľúč.slová neutron stars equation of state condensation Jazyk dok. angličtina Krajina Holandsko Systematika 53 Anotácia We extend relativistic mean-field models with hadron masses and meson–baryon coupling constants dependent on the scalar field σ, including hyperons and (1232)baryons, to incorporate a possibility of the charged ρmeson condensation in neutron star matter. The influence of the ρ−condensation on the equation of state proves to be strongly model dependent. In our models of one type (KVORcut-based ones) the ρ−condensation arises by a second-order phase transition above a critical density and the maximum value of the neutron star mass diminishes only slightly. The matter composition changes more significantly. In our models of other type (MKVOR*-based ones), if the system is considered at fixed density, the ρ−condensation arises by a second-order phase transition at the baryon density n =n(II)c,ρand at a slightly higher density n =n(I)c,ρthere occurs a first-order phase transition. In a neutron star matter starting with a density n <n(II)c,ρthere appears a region of a mixed phase, or the system is described by Maxwell construction, that results in a substantial decrease of the value of the maximum neutron star mass. Nevertheless in the models under consideration the observational constraint on the maximum neutron star mass is fulfilled. Besides, in MKVOR*-based models the appearance of the ρ−condensate is accompanied by a strong rearrangement of the matter composition. Dependence of the results on a choice of the ρmeson scaling functions for the effective ρmeson mass and coupling constants is also investigated URL Link na plný text Kategória publikačnej činnosti ADC Číslo archívnej kópie 43905 Katal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Báza dát xpca - PUBLIKAČNÁ ČINNOSŤ Odkazy PERIODIKÁ-Súborný záznam periodika nerozpoznaný