Effect of Resonant Neutrino Oscillation on TeV Neutrino Flavor Ratio from Choked GRBs

Oscillation of high-energy neutrinos from choked jets in stellar and merger ejecta

We present a comprehensive study on oscillation of high-energy neutrinos from two different environments: blue supergiant progenitors that may harbor low-power gamma-ray burst (GRB) jets and neutron star merger ejecta that would be associated with short gamma-ray bursts. We incorporate the radiation constraint that gives a necessary condition for nonthermal neutrino production, and account for the time evolution of the jet, which allows us to treat neutrino oscillation in matter more accurately. For massive star progenitors, neutrino injection inside the star can lead to nonadiabatic oscillati…

Inspecting the supernova gamma-ray burst connection with high-energy neutrinos

Long-duration gamma-ray bursts (GRBs) have been often considered as the natural evolution of some core-collapse supernovae (SNe). While GRBs with relativistic jets emit an electromagnetic signal, GRBs with mildly relativistic jets are opaque to photons and, therefore, could be detectable through neutrinos only. We discuss the possibility that successful GRBs and mildly relativistic jets belong to the same class of astrophysical transients with different Lorentz factor Gamma_b and study the production of high-energy neutrinos as a function of Gamma_b, by including both proton-photon and proton-…

双中子星合并与稀有核心坍缩超新星中低能中微子湮灭对高能中微子的影响

Effects of Annihilation with Low-Energy Neutrinos on High-Energy Neutrinos from Binary Neutron Star Mergers and Rare Core-Collapse Supernovae

本文研究了双中子星合并和稀有核心坍缩超新星中，窒息喷流产生的高能中微子与吸积盘低能中微子的湮灭效应，发现该效应会显著改变高能中微子的全味谱和味组成，需在精确测量中予以考虑。

Astrophysical neutrino flavor ratios in the presence of sterile neutrinos

Astrophysical objects such as active-galactic nuclei (AGN) and gamma-ray bursts (GRBs) can be sources of high energy, astrophysical neutrinos. The decay of charged pions produces electron and muon-flavor neutrinos from the primary decay of the pion, and from the secondary decay of the resulting charged lepton. At low energies we expect the flavor ratio $Φ_{ν_e}:Φ_{ν_μ}:Φ_{ν_τ}$ to be $1:2:0$ at the source. We are interested in the flavor ratios as measured on Earth after the neutrinos propagate over cosmic distance scales from the source. If we only consider vacuum flavor transition probabilit…

Magnetic Field and Flavor Effects on the Gamma-Ray Burst Neutrino Flux

We reanalyze the prompt muon neutrino flux from gamma-ray bursts (GRBs), at the example of the often used reference Waxman-Bahcall GRB flux, in terms of the particle physics involved. We first reproduce this reference flux treating synchrotron energy losses of the secondary pions explicitly. Then we include additional neutrino production modes, the neutrinos from muon decays, the magnetic field effects on all secondary species, and flavor mixing with the current parameter uncertainties. We demonstrate that the combination of these effects modifies the shape of the original Waxman-Bahcall GRB f…

Neutrino conversions in cosmological gamma-ray burst fireballs

We study neutrino conversions in a recently envisaged source of high-energy neutrinos (E \geq 10^6 GeV), that is, in the vicinity of cosmological Gamma-Ray Burst fireballs (GRB). We consider the effects of flavor and spin-flavor conversions and point out that in both situations, a some what higher than estimated high energy tau neutrino flux from GRBs is expected in new km^2 surface area under water/ice neutrino telescopes.

High Energy Neutrinos from Cosmological Gamma-Ray Burst Fireballs

Observations suggest that $γ$-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a relativistic fireball. We show that a large fraction, $\ge 10%$, of the fireball energy is expected to be converted by photo-meson production to a burst of $\sim10^{14} eV$ neutrinos. A km^2 neutrino detector would observe at least several tens of events per year correlated with GRBs, and test for neutrino properties (e.g. flavor oscillations, for which upward moving $τ$'s would be a unique signature, and coupling to gravity) with an accuracy many orders of magnitude better than is curren…

High Energy Neutrinos from Gamma-Ray Bursts

Observations suggest that gamma-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a relativistic fireball. In this talk, recent work on the production of high energy neutrinos by GRB fireballs is reviewed. A significant fraction of GRB energy is expected to be converted to an accompanying burst of high energy neutrinos. Photomeson interactions produce a burst of ~100 TeV neutrinos in coincidence with the GRB, and a burst of \~10^18 eV neutrinos following the GRB on a time scale of 10 s. Inelastic p-n nuclear collisions result in the production of a burst of ~10 GeV neu…

Photohadronic Origin of the TeV-PeV Neutrinos Observed in IceCube

We perform an unbiased search of the origin of the recently observed 28 events above ~30 TeV in the IceCube neutrino observatory, assuming that these are (apart from the atmospheric background) of astrophysical origin produced by photohadronic interactions. Instead of relying on the normalization of the neutrino flux, we demonstrate that spectral shape and flavor composition can be used to constrain or identify the source class. In order to quantify our observations, we use a model where the target photons are produced by the synchrotron emission of co-accelerated electrons, and we include mag…