Neutrino reaction rates in neutron star matter with

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Neutrino reaction rates in neutron star matter with isobars Yanjun Chen Center for Astrophysics

Neutrino reaction rates in neutron star matter with isobars Yanjun Chen Center for Astrophysics University of Science and Technology of China CSQCDII Beijing China 20 th – 24 th May 2009 1

Composition of neutron stars l Nucleons, leptons l Hyperons, -isobars l Pion/Kaon condensation l

Composition of neutron stars l Nucleons, leptons l Hyperons, -isobars l Pion/Kaon condensation l Quarks 2

 -isobars in nuclear matter Properties of -isobars – ~ 1232 Me. V –

-isobars in nuclear matter Properties of -isobars – ~ 1232 Me. V – Spin-3/2 and isospin-3/2 – Belong to the decuplet of group Constraints of couplings between s and mesons in nuclear matter ■ l ■ SU(3) g / g l – There are no real -isobars present at the saturation density of nuclear g / g matter and in the ground state of finite nuclei Kosov et al, Phys. Lett. B (1998) – The mixed -nucleon phase is a metastable state – Finite-density QCD sum-rule calculations (Jin, Phys. Rev. C, 1995) 3

Composition of neutron star matter with s T=30 Me. V, neutrino-free case T=30 Me.

Composition of neutron star matter with s T=30 Me. V, neutrino-free case T=30 Me. V, neutrino-trapped case 4 Chen et al, Phys. Rev. C, 75, 035806 (2007)

Composition of neutron star matter with hyperons (and s) T=0, with hyperons and s

Composition of neutron star matter with hyperons (and s) T=0, with hyperons and s Dexheimer & Schramm, APJ, 683, 943 (2008) 5

Microphysics of Neutrino reaction rates Neutral current reactions Charged current reactions 6

Microphysics of Neutrino reaction rates Neutral current reactions Charged current reactions 6

Microphysics of Neutrino scattering rates E ’ p+q E p E E ’ G

Microphysics of Neutrino scattering rates E ’ p+q E p E E ’ G is the Rarita-Schwinger propagator Rarita & Schwinger, Phys. Rev. , 60, 61 (1941) 7

l Neutral currents: constituent quark models l Charged currents: generalization of conserved vector current

l Neutral currents: constituent quark models l Charged currents: generalization of conserved vector current theory – Electromagnetic and weak vector currents constitute the octet [8] [10] [10*] = [64] [27] [8] [1] Chen et al (2009) 8

Neutrino scattering rates l Neutral currents: – Inelastic scattering +N +l + Chen et

Neutrino scattering rates l Neutral currents: – Inelastic scattering +N +l + Chen et al 9

l Large vector coupling of – |CV| ~ 2 l Higher spin of s

l Large vector coupling of – |CV| ~ 2 l Higher spin of s opens additional phase space to scatter Chen et al 10

Neutrino mean free paths of neutral currents Chen et al (2007) 11

Neutrino mean free paths of neutral currents Chen et al (2007) 11

Neutrino mean free paths of charged currents l Charged currents: e- + p e

Neutrino mean free paths of charged currents l Charged currents: e- + p e + n e + - e- + + e + + e- + ++ e + N ( ) e- + (N) Chen et al, Phys. Rev. C, 79, 055802 (2009) 12

Yuan & Jeremy, MNRAS, 360, 1493 (2005) 13

Yuan & Jeremy, MNRAS, 360, 1493 (2005) 13

Yuan & Jeremy, MNRAS, 360, 1493 (2005) 14

Yuan & Jeremy, MNRAS, 360, 1493 (2005) 14

Conclusions l -isobars may exist in neutron star matter. l For neutrino opacities in

Conclusions l -isobars may exist in neutron star matter. l For neutrino opacities in neutron stars, the s would affect, even be dominant. l Proto-neutron stars are a possible site for testing s by the signals of neutrinos and gravitational waves. But it needs further studies… 15

Thanks ! 16

Thanks ! 16