Title: Neutrino reaction rates in neutron star matter with ?-isobars
1Neutrino reaction rates in neutron star matter
with ?-isobars
- Yanjun Chen
- Center for Astrophysics
- University of Science and Technology of China
CSQCDII Beijing China 20th 24th May 2009
2Composition of neutron stars
- Nucleons, leptons
- Hyperons, ?-isobars
- Pion/Kaon condensation
- Quarks
3?-isobars in nuclear matter
- Properties of ?-isobars
- 1232 MeV
- Spin-3/2 and isospin-3/2
- Belong to the decuplet of group SU(3)
- Constraints of couplings between ?s and mesons in
nuclear matter - There are no real ?-isobars present at the
saturation density of nuclear matter and in the
ground state of finite nuclei - The mixed ?-nucleon phase is a metastable state
- Finite-density QCD sum-rule calculations (Jin,
Phys.Rev.C,1995)
g?? / g?
g?? / g?
Kosov et al, Phys.Lett.B (1998)
4Composition of neutron star matter with ?s
T30MeV, neutrino-free case
T30MeV, neutrino-trapped case
Chen et al, Phys.Rev.C, 75, 035806 (2007)
5Composition of neutron star matter with hyperons
(and ?s)
T0, with hyperons
T0, with hyperons and ?s
Dexheimer Schramm, APJ, 683, 943 (2008)
6Microphysics of Neutrino reaction rates
Charged current reactions
Neutral current reactions
7Microphysics of Neutrino scattering rates
G? is the Rarita-Schwinger propagator
Rarita Schwinger, Phys.Rev., 60, 61 (1941)
8- Neutral currents
- constituent quark models
- Charged currents
- generalization of con- served vector
current theory - Electromagnetic and weak vector currents
constitute the octet 8
10 ? 10 64 ? 27 ? 8 ? 1
Chen et al (2009)
9Neutrino scattering rates
- Neutral currents
- Inelastic scattering
- ? N ? N
? l ? l
? ? ? ?
Chen et al (2007)
10- Large vector coupling of ?-
- CV 2
- Higher spin of ?s opens additional phase space to
scatter
Chen et al (2007)
11Neutrino mean free paths of neutral currents
Chen et al (2007)
12Neutrino mean free paths of charged currents
- Charged currents
- ?e n e- p
?e ?- e- ?
?e ? e- ?
?e N (?) e- ? (N)
Chen et al, Phys. Rev. C, 79, 055802 (2009)
13Yuan Jeremy, MNRAS, 360, 1493 (2005)
14Yuan Jeremy, MNRAS, 360, 1493 (2005)
15Conclusions
- ?-isobars may exist in neutron star matter.
- For neutrino opacities in neutron stars, the ?s
would affect, even be dominant. - Proto-neutron stars are a possible site for
testing ?s by the signals of neutrinos and
gravitational waves. But it needs further
studies
16Thanks !