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2006 Fiscal Year Final Research Report Summary

Baryon Superfluidity and Neutrino Cooling of Neutron Stars

Research Project

Project/Area Number 16540225
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionIwate University

Principal Investigator

TAKATSUKA Tatsuyuki  Iwate University, Faculty of Humanities and Social Sciences, Professor, 人文社会科学部, 教授 (50043427)

Project Period (FY) 2004 – 2006
KeywordsNeutron Star / Hyperon / Superfluidity / Cooling / Pion Condensation
Research Abstract

Baryon superfluidity and neutrino emissibity are investigated for normal and hyperon-mixed neutron stars and the physical inputs necessary for neutron star cooling calculations are presented. By perfuming the cooling calculations, it is found that the so-called "hyperon cooling" (hyperon direct URCA process) combined with hyperon superfluidity is a promising candidate for a fast nonstandard cooling scenario responsible for some neutron stars which are too cold to be explained by the standard cooling, namely, the modified URCA process.
However this hyperon cooling breaks down due to the disappearance of Λ-superfluidity; if a less attractive ΛΛ interaction suggested recently by the "NAGARA event" (_<Λ^^6Λ>He) becomes definite. In this context, a possibility of Λ-superfluid due to the ΛΣ^-pairing instead of ΛΛ one is discussed by formulating the BCS theory for the case with different Fermi surfaces.
As another fast cooling scenario, "pion cooling" is also investigated. The superfluid energy gap of quasibaryons under the combined pion condensation with Δ-Isobar effects is calculated by extending the BCS formalism to the quasibaryon pairing and constructing the pair state to utilize most efficiently the ^3P_2 attraction. The energy gap of (0.1〜1) MeV is found, which means that only the pion cooling can be a fast cooling scenario compatible with observations when the hyperon cooling does not hold.

  • Research Products

    (12 results)

All 2007 2006 2004

All Journal Article (12 results)

  • [Journal Article] Baryonic ^3P_2-Dominant Superfluidity under Combined Pion Condensation with Δ Isobax. II2007

    • Author(s)
      R.Tamagaki
    • Journal Title

      Progress of Theoretical Physics 117・5

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Baryonic ^3P_2-Dominant Superfluidity under Combined Pion Condensation with Δ Isobar. II -Properties of Pairing Interaction and Numerical Results-2007

    • Author(s)
      R.Tamagaki, T.Takatsuka
    • Journal Title

      Progress Theoretical Physics Vol.117, No.5

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Baryonic ^3P_2-Dominant Superfluidity under Combined Pion Condensation with Δ-Mixing2006

    • Author(s)
      R.Tamagaki
    • Journal Title

      Progress of Theoretical Physics 115・1

      Pages: 245-250

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Occurence of Hyperon Superfluidity in Neutron Star Cores2006

    • Author(s)
      T.Takatsutka
    • Journal Title

      Progress of Theoretical Physics 115・2

      Pages: 355-379

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Baryonic ^3P_2-Dominant Superfluidity under Combined Pion Condensation with Δ Isobax. I2006

    • Author(s)
      R.Tamagaki
    • Journal Title

      Progress of Theoretical Physics 116・2

      Pages: 573-599

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Baryonic ^3P_2-Dominant Superfluidity under Combined Pion Condensation with Δ-Mixing2006

    • Author(s)
      R.Tamagaki, T.Takatsuka
    • Journal Title

      Progress Theoretical Physics Vol.115, No.1

      Pages: 245-250

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Occurrence of Hyperon Superfluidity in Neutron Star Cores2006

    • Author(s)
      T.Takatsuka, S.Nishizaki, Y.Yamamoto, R.Tamagaki
    • Journal Title

      Progress Theoretical Physics Vol.115, No.2

      Pages: 355-379

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Baryonic ^3P_2-Dominat Superfluidity under Combined Pion Condensation with Δ Isobar. I2006

    • Author(s)
      R.Tamagaki, T.Takatsuka
    • Journal Title

      Progress Theoretical Physics Vol.116, No.3

      Pages: 573-599

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Hyperon-Mixed Neutron Stars2004

    • Author(s)
      T.Takatsutka
    • Journal Title

      Progress of Theoretical Physics, Supplement No.156

      Pages: 84-103

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Baryon Superfluidity and Neutrino Emissibity of Neutron Stars2004

    • Author(s)
      T.Takatsutka
    • Journal Title

      Progress of Theoretical Physics 122・1

      Pages: 37-72

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Hyperon-Mixed Neutron Stars2004

    • Author(s)
      T.Takatsuka
    • Journal Title

      Progress Theoretical Physics No.156(Supplement)

      Pages: 84-103

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Baryon Superfluidity and Neutrino Emissibity of Neutron Stars2004

    • Author(s)
      T.Takatsuka, R.Tamagaki
    • Journal Title

      Progress Theoretical Physics Vol.112, No.1

      Pages: 37-72

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2008-05-27  

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