Strongest gravitational waves from neutrino oscillationsat supernova core bounce

Resonant active-to-active ( $\nu_{\mathrm {a}} \rightarrow \nu_{\mathrm {a}}$ ), as well as active-to-sterile ( $\nu_{\mathrm {a}} \rightarrow \nu_{\mathrm {s}}$ ) neutrino ( $\nu$ ) oscillations can take place during the core bounce of a supernova collapse. Besides, over this phase, weak magnetism increases the antineutrino ( $\bar{\nu}$ ) mean free path, and thus its luminosity. Because the oscillation feeds mass-energy into the target $\nu$ species, the large mass-squared difference between the species ( $\nu_{\mathrm {a}} \rightarrow \nu_{\mathrm {s}}$ ) implies a huge amount of energy to be given off as gravitational waves ( $L_{\mathrm{GW}} \sim 10^{49}$ erg s-1), due to anisotropic but coherent $\nu$ flow over the oscillation length. This asymmetric $\nu$ -flux is driven by both the spin-magnetic and the universal spin-rotation coupling. The novel contribution of this paper stems from (1) the new computation of the anisotropy parameter $\alpha \sim 0.1$ -0.01, and (2) the use of the tight constraints from neutrino experiments as SNO and KamLAND, and the cosmic probe WMAP, to compute the gravitational-wave emission during neutrino oscillations in supernovae core collapse and bounce. We show that the mass of the sterile neutrino $\nu_{\mathrm {s}}$ that can be resonantly produced during the flavor conversions makes it a good candidate for dark matter as suggested by Fuller et al. , Phys. Rev. D 68, 103002 (2003). The new spacetime strain thus estimated is still several orders of magnitude larger than those from $\nu$ diffusion (convection and cooling) or quadrupole moments of neutron star matter. This new feature turns these bursts into the more promising supernova gravitational-wave signals that may be detected by observatories as LIGO, VIRGO, etc., for distances far out to the VIRGO cluster of galaxies.