Collective neutrino oscillations and detectabilities in failed supernovae

We investigate the collective neutrino oscillations under the three-flavor multiangle approximation in a spherically symmetric simulation of failed supernovae. A failed supernova emits high neutrino fluxes in a short time, while intense accretion proceeds with a high enough electron density to experience recollapse into a black hole. Our results show that matter-induced effects completely dominate over neutrino self-interaction effects and multiangle matter suppression occurs at all time snapshots we studied. These facts suggest that only Mikheyev-Smirnov-Wolfenstein resonances affect the neutrino flavor conversions in failed supernovae and simple spectra will be observed at neutrino detectors. We also estimate the neutrino event rate in current and future neutrino detectors from a source at 10 kpc as a Galactic event. The time evolution of neutrino detection could provide information about the dense and hot matter and constrain the neutrino mass ordering problem.

Figure 1

Luminosities (top) and average energies (bottom) of ${\nu }_e$ (red line), ${\overline{\nu }}_e$ (blue line), and ${\nu }_x$ (green) as functions of $t_{\mathrm{pb}}$.

Figure 2

Density profiles at $t_{\mathrm{pb}}=30$, 100, 500, 600 ms.

Figure 3

The time evolution of the asymmetry parameter $\epsilon$.

Figure 4

The radial evolution of $P_{ee}$ at 20 MeV in the standard case (red solid line), the low-density case (green solid line), and the single-angle case (blue solid line) at $t_{\mathrm{pb}}=600\mathrm{ms}$.

Figure 5

The strength of the matter interaction $\lambda$ and neutrino self-interaction $\mu$ with the radial coordinate at $t_{\mathrm{pb}}=600\mathrm{ms}$.

Figure 6

The radial evolution of $P_{ee}$ at 20 MeV in the standard case (red solid line) and the low-density case (green dotted line) at 30 (left), 100 (middle), and 500 ms (right).

Figure 7

The strength of the matter interaction $\lambda$ and neutrino self-interaction $\mu$ with the radial coordinate at 30 (left), 100 (middle), and 500 ms (right).

Figure 8

The unstable region where $\mathrm{Im}(\mathrm{\Omega })r>1$ (red-shaded region) and the multiangle matter potential ${\lambda }^{*}$ for the density profile (blue line) at $t_{\mathrm{pb}}=600\mathrm{ms}$. The density profile does not intersect the MAA unstable regions at any radius.

Figure 9

The event rate (top) and accumulated event number (bottom) at Super-Kamiokande from a failed supernova at $d=10\mathrm{kpc}$. The inverted mass ordering, normal mass ordering, and no-oscillation cases are shown by the red solid, blue dashed, and green dotted lines, respectively.

Figure 10

The event rate (top) and accumulated event number (bottom) at Hyper-Kamiokande from a failed supernova at $d=10\mathrm{kpc}$. The inverted mass ordering, normal mass ordering, and no-oscillation cases are shown by the red solid, blue dashed, and green dotted lines, respectively.

Figure 11

The event rate (top) and accumulated event number (bottom) at DUNE from a failed supernova at $d=10\mathrm{kpc}$. The inverted mass ordering, normal mass ordering, and no-oscillation cases are shown by the red solid, blue dashed, and green dotted lines, respectively.