Based on recent improvements of the supernova electron antineutrino emission model, we update the limit on neutrino mass from the SN1987A data collected by Kamiokande-II, IMB and Baksan. We derive the limit of 5.8 eV at 95% CL, that we show to be remarkably insensitive to the astrophysical uncertainties. Also we evaluate the ultimate mass sensitivity of this method for a detector like Super-Kamiokande. We find that the bound lies in the sub-eV region, 0.8 eV at 95 % CL being a typical outcome, competitive with the values that are presently probed in laboratory. However, this bound is subject to strong statistical fluctuations, correlated to the characteristics of the first few events detected. We briefly comment on the prospects offered by future detectors.

The induced gravitational collapse (IGC) paradigm of long gamma-ray bursts (GRBs) associated with supernovae (SNe) predicts a copious neutrino-antineutrino (νν) emission owing to the hypercritical accretion process of SN ejecta onto a neutron star (NS) binary companion. The neutrino emission can reach luminosities of up to 10 57 MeV s −1 , mean neutrino energies 20 MeV, and neutrino densities 10 31 cm −3 . Along their path from the vicinity of the NS surface outward, such neutrinos experience flavor transformations dictated by the neutrino to electron density ratio. We determine the neutrino and electron on the accretion zone and use them to compute the neutrino flavor evolution. For normal and inverted neutrino-mass hierarchies and within the two-flavor formalism (ν e ν x ), we estimate the final electronic and non-electronic neutrino content after two oscillation processes: (1) neutrino collective effects due to neutrino self-interactions where the neutrino density dominates and, (2) the Mikheyev-Smirnov-Wolfenstein (MSW) effect, where the electron density dominates. We find that the final neutrino content is composed by ∼55% (∼62%) of electronic neutrinos, i.e. ν e +ν e , for the normal (inverted) neutrino-mass hierarchy. The results of this work are the first step toward the characterization of a novel source of astrophysical MeV-neutrinos in addition to core-collapse SNe and, as such, deserve further attention.

ABSTRACT:We study the possible suppression of the extragalactic neutrino flux due to a nonstandard interaction during its propagation. In particular, we study neutrino interaction with an ultra-light scalar field dark matter. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a new mechanism to reduce the ultra-high energy neutrino flux. We study both the cases of non-self-conjugate as well as self-conjugate dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms for the reduction of the neutrino flux.

We study the consequences on the neutrino oscillation parameter space, mixing angle (tan 2 ), and vacuum mass difference (Ám 2 0 ) when mass varying neutrino (MaVaN) models are assumed in a supernova environment. We consider electronic to sterile channels e ! s and " e ! " s in two-flavor scenario. In a given model of MaVaN mechanism, we induce a position-dependent effective mass difference, Ám 2 ðrÞ, where r is the distance from the supernova core, that changes the neutrino and antineutrino flavor conversion probabilities. We study the constraints on the mixing angle and vacuum mass difference coming from r-process and the SN1987A data. Our result is the appearance of a new exclusion region for very small mixing angles, tan 2 ¼ 10 À6 -10 À2 , and small vacuum mass difference, Ám 2 0 ¼ 1-20 eV 2 , due the MaVaN mechanism.