Vector current conservation and neutrino emission from singlet-paired baryons in neutron stars

2006

Neutrino emission caused by singlet Cooper pairing of baryons in neutron stars is recalculated by accurately taking into account for conservation of the vector weak currents. The neutrino emissivity via the vector weak currents is found to be several orders of magnitude smaller than that obtained before by different authors. This makes unimportant the neutrino radiation from singlet pairing of protons or hyperons.

Relativistic approach to positronium levels in a strong magnetic field

2001

We have investigated the bound states of an electron and positron in superstrong magnetic fields typical for neutron stars. The complete relativistic problem of positronium in a strong magnetic field has not been succesfully solved up to now. In particular, we have studied the positronium when it moves relativistically across the magnetic field. A number of problems which deal with the pulsar magnetosphere, as well as the evolution of protoneutron stars, could be considered as a field for application.

Direct URCA process in neutron stars with strong magnetic fields

1997

We calculate the emissivity for the direct URCA process in strongly magnetized, degenerate matter in neutron stars, under $\beta $-equilibrium. We show that, if the magnetic field is large enough for protons and electrons to be confined to the ground Landau levels, the field-free threshold condition on proton concentration no longer holds, and direct URCA reactions are open for an arbitrary proton concentration. Direct URCA process leads to an early phase of fast neutron star cooling. This circumstance allows us to constrain the initial magnetic field inside observed pulsars.

Neutrino-pair emission due to electron-phonon scattering in a neutron star crust: a reappraisal

2000

The process of $\nu \bar{\nu}$ radiation due to interaction of electrons with phonons in the crust of a cooling neutron star is studied with the consistent account of an electromagnetic coupling between electrons in the medium. The wavelength of radiated neutrinos and antineutrinos is typically much larger than the electron Debye screening distance in the medium, and therefore plasma polarization substantially modifies the effective weak current of the electron. Is shown, that under above conditions plasma polarization screens totally a vector weak interaction of the electron with a neutrino field. As a result, the $\nu \bar{\nu}$ emissivity is less in approximately 2.23 times than previous…

Plasma effects on neutrino-antineutrino synchrotron radiation in dense matter

2000

Abstract We consider plasma effects on ν ν synchroton radiation from ultrarelativistic, degenerate electrons in neutron stars with strong magnetic fields. Under typical conditions for such stars, a semiclassical calculation can be performed, in which electrons are considered to move along classical paths. We show that collective effects in the plasma lead to an essential enhancement (about three times) of the vector weak-current contributions to neutrino pair emissivity.

Neutrino Bremsstrahlung from electrons in neutron star crusts

2001

The process of v (v) over bar Bremsstrahlung via electron scattering off nuclei in the crust of a cooling neutron star is studied within the Random Phase Approximation. We show that the electromagnetic plasma screens the vector weak coupling of electrons with the neutrino field. This screening effect takes place in both the crystalline and liquid phase of the neutron star crust, when the momentum carried out by the neutrino pair is smaller than the inverse Debye screening distance of the electrons. This condition holds in the crust volume at temperatures and densities where the electron Bremsstrahlung dominates the neutrino production. As a result, the vector weak current contribution to th…

Neutrino emission due to Cooper pairing of protons in cooling neutron stars: Collective effects

2000

The process of neutrino-pair radiation due to formation and breaking of Cooper pairs of protons in superconducting cores of neutron stars is considered with taking into account of the electromagnetic coupling of protons to ambient electrons. It is shown that plasma polarization strongly modifies the effective vector weak current of protons. Collective response of ambient electrons to the proton quantum transition contributes coherently to the complete interaction with the neutrino field and enhances the rate of neutrino-pair production by two orders of magnitude.

Erratum to: “Relativistic direct Urca processes in cooling neutron stars”

2001

Relativistic direct Urca processes in cooling neutron stars

2001

We derive a relativistic expression for neutrino energy losses caused by the direct Urca processes in degenerate baryon matter of neutron stars. We use two different ways to calculate the emissivity caused by the reactions to our interest. First we perform a standard calculation by Fermi's ''golden'' rule. The second calculation, resulting in the same expression, is performed with the aid of polarization functions of the medium. Our result for neutrino energy losses strongly differs from previous non-relativistic results. We also discuss nonconservation of the baryon vector current in reactions through weak charged currents in the medium, when the asymmetry between protons and neutrons is c…