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Influence of Phase-Transition-Scenarios on the Neutron Star Characteristics Abrupt Changes Triggered by the Formation

Influence of Phase-Transition-Scenarios on the Neutron Star Characteristics Abrupt Changes Triggered by the Formation of Quark Phase G. B. Alaverdyan. Nnnn. Yerevan State University, Armenia.

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Influence of Phase-Transition-Scenarios on the Neutron Star Characteristics Abrupt Changes Triggered by the Formation

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  1. Influence of Phase-Transition-Scenarios on the Neutron Star Characteristics Abrupt Changes Triggered by the Formation of Quark Phase G. B. Alaverdyan Nnnn • Yerevan State University, Armenia 2nd Int. Conf. “The Modern Physics of Compact Stars andRelativistic Gravity” Sept. 18-21, 2013, Yerevan

  2. Introduction D. D. Ivanenko, D. F. Kurdgelaidze, Astrofizika 1, 479, 1965 • Two scenarios for hadron-quark phase transition: • Maxwell scenario • ordinary first-order phase transition at constant • pressure with a density jump • Glendenning scenario • formation of mixed hadron-quark matter with a • continuous variation of pressure and density • (N. K. Glendenning, Phys. Rev. D46, 1274, 1992) Mixed phase is energetically favorable for small values of the surface tension H. Heiselberg, M. Hjorth-Jensen, Phys. Rep. 328, 237, 2000

  3. Model EOS for Compact Stars Hadronic Matter EOS RMF Lagrangian density of many-particle system of p, n, , , , 

  4. Relativistic mean-field approach

  5. Parametric EOS for nuclear matter the asymmetry parameter

  6. Parameters of RMF theory Symmetric nuclear matter Saturation density Binding energy per baryon

  7. Parameters of RMF theory compressibility module Symmetry energy

  8. Parameters of RMF theory

  9. Characteristics of -equilibrium npe- plasma G. B. Alaverdyan, Research in Astron. Astrophys,10, 1255, 2010

  10. EOS of quark phase Improved version of MIT bag model Interactions between u, d, s quarks in one-gluon exchange approximation E. Farhi, R. L. Jaffe, Phys. Rev. D30, 2379, 1984

  11. Density discontinuity parameter • Seidov criterion (H. Seidov, Astron. Zh. 48, 443, 1971 ) If neutron star with infinitesimal quark core is unstable Glend. Maxw.

  12. Constituents population

  13. Changes in the Stellar Parameters

  14. Catastrophic conversion due to deconfinement phase transition

  15. Summary and conclusions • We calculate the neutron star matter EOS with quark-deconfinement phase transitions • corresponding to the Maxwell and Glendenning scenarios. • We find the dependence of conversion energy on the baryonic mass of neutron stars • and analyze the changes in stellar radiuses due to the deconfinement phase transition. • We show that for a fixed value of the baryonic mass of star the conversion energy • in the case of Glendenning construction more than in the case of Maxwell • construction. • It is found that in the case of the Maxwell construction, the minimum required • baryonic mass for the catastrophic rearrangement of the neutron star and the formation • of a quark core in the center of the star is greater than in the case of Glendenning one. • In the studied case, the quark deconfinement phase transition in the neutron • star interior leads to the energy release of the order erg.

  16. ՇՆՈՐՀԱԿԱԼՈՒԹՅՈՒՆ THANK YOU

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