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Department of Physics, Sungkyunkwan University

Application of the Quark-meson coupling model to dense nuclear matter. 2005 KPS Meeting Chon Buk University. C. Y. Ryu , C. H. Hyun, and S. W. Hong. Department of Physics, Sungkyunkwan University. Application.  + in nuclear matter Hadron masses in neutron stars

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Department of Physics, Sungkyunkwan University

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  1. Application of the Quark-meson coupling model to dense nuclear matter 2005 KPS Meeting Chon Buk University C. Y. Ryu, C. H. Hyun, and S. W. Hong Department of Physics, Sungkyunkwan University

  2. Application • + in nuclear matter • Hadron masses in neutron stars • kaon condensation in neutron stars with hyperons Outline • Introduction • - The quark-meson coupling (QMC) model • Results and summaries

  3. Introduction T (MeV) ~150

  4. Quark-meson coupling (QMC) model σ, ω • QMC Lagrangian in mean field approximation

  5. Meson fields in QMC model σ meson field : ωmeson field :

  6. MQMC model • Effective mass of a baryon Bag energy of a baryon Effective mass of a baryon

  7. Effective mass of + + in symmetry nuclear matter + (1540 MeV) : uudds

  8. The effective mass of Θ+ in nuclear matter

  9. Decay of + in medium

  10. Chemical potential of + Chemical potential of K and N • Chemical potential of K, N, + in medium

  11. Comparison between  and K + N

  12. Summaries • The effective mass of + in naïve quark model. • The possibility of decay of + in medium.

  13. Hadron masses in neutron stars

  14. Scaled effective Lagrangian

  15. Energy density .vs. pressure Energy density Pressure

  16. Equation of state

  17. Mass-radius relation of neutron star • Tolman-Oppenheimer-Volkoff equation • Mass of neutron star

  18. The mass-radius relation of neutron star

  19. Scaled effecive Lagrangian • The maximum mass and radius of • neutron star increase. Summaries • The observed compact stars • MJ0751+1807 = (2.2  0.2) M, • M4U1700-37 = (2.44  0.2) M

  20. Exotic phenomena in Neutron star Kaon condensation in neutron star with hyperons

  21. J. Schaffner-Bielich, V. Koch & M. Effenberger, Nucl. Phys. A669 (2000) 153. A. Ramos & E. Oset, Nucl. Phys. A671 (2000) 481. A. Cieply, E. Friedman, A. Gal & J. Mares, Nucl. Phys. A696 (2001) 173. Shallow optical potential V0+iW0=-50 –i 60 MeV Deep optical potential V0+iW0= -120– i10 MeV Y. Akaishi & T. Yamazaki, Phys. Rev. C65 (2002) 044005. N. Kaiser, P.B. Siegel & W. Weise, Nucl. Phys. A594 (1995) 325. K- optical potential

  22. Strange tribaryons S0(3115) and S+(3140) Very strong attraction between K- and nucleons KEK PS-E471

  23. OZI rule : s-quark doesn’t interact with u(d)-quark • assume only s-s quarks interaction : • strange meson fields, • scalar σ* (f0=975 MeV) and vector φ (=1020 MeV) • Theory - the extended QMC model Quark-meson coupling (QMC) model : MIT bag model + σ – ω - ρ mesons

  24. The extended QMC model for baryon octet σ – ω–ρ (only u(d) quark) + σ* – φ (only s quark) Lagrangian density for baryon octet B = p, n, Λ, Σ+, Σ0, Σ-, Ξ0, Ξ- l = e, μ

  25. Effective mass of a baryon Bag energy of a baryon Effective mass of a baryon

  26. K- in neutron star matter with hyperons Kaon Lagrangian : Effective mass of a kaon : Real part of optical potential at the saturation density UK (ρ0) = - gσK σ (ρ0)– gωK ω (ρ0) |UK (ρ0)| = 80, 100, 120 and 140 MeV

  27. Meson fields on kaon condensation σ meson : σ* meson : ω meson : φ meson : ρ meson :

  28. Chemical equilibrium : μK = μe • Charge neutrality : - n K = 0 • Baryon number conservation : Three conditions in neutron stars

  29. Chemical potential Dispersion relation for s-wave condensation for K- (us) Baryon energy Chemical potential of baryons and kaon μK = ωK

  30. gσK : free parameter Coupling constants • Quark counting rule and SU(6) symmetry

  31. Results Relative populations in neutron star

  32. Relative populations in neutron star

  33. Relative populations in neutron star

  34. Relative populations in neutron star

  35. Relative populations in neutron star

  36. Equation of state(Energy density vs. Pressure) Energy density Pressure

  37. Equations of state

  38. Mass-radius relation of neutron star • Tolman-Oppenheimer-Volkoffequation • Mass of neutron star

  39. The mass-radius relation of neutron star

  40. 2. The possibility of very deep optical potential (phases) - shallow : nuclear- hyperonic -Kaonic+hyperonic phase - deep : nuclear – kaonic – kaonic+hyperonic phase Summaries • The populations of particles and the EoS are very sensitive to the values of optical potential. The values have to be fixed by experiments. 3. As UK increases, the EoS becomes softer at low densities, while becomes stiffer at high densities. Deep potential The light and small neutron stars

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