相关论文: Constraints on Dirac Neutrinos from SN 1987A
The supernova (SN) neutronization phase produces mainly electron ($\nu_e$) neutrinos, the oscillations of which must take place within a few mean-free-paths of their resonance surface located nearby their neutrinosphere. The…
Neutrino masses remain a significant unsolved problem in physics and their nonzero value proves the Standard Model is incomplete. Currently, the values of the three masses only have upper limits from cosmology and experiments like KATRIN.…
Spin-flavor oscillations of Dirac neutrinos in matter and a magnetic field are studied using the method of relativistic quantum mechanics. Using the exact solution of the wave equation for a massive neutrino, taking into account external…
We explore the role of neutrinos in a Quark Nova explosion. We study production of neutrinos during this event, their propagation and their interactions with the surrounding quark matter and neutron-rich envelope. We address relevant…
The shape of the neutrino pulse from the supernova SN1987a provides one of the most stringent constraints on the size of large, compact, "gravity-only" extra dimensions. Previously, calculations have been carried out for a newly-born…
Majoron-like bosons would emerge from a supernova (SN) core by neutrino coalescence of the form $\nu\nu\to\phi$ and $\bar\nu\bar\nu\to\phi$ with 100 MeV-range energies. Subsequent decays to (anti)neutrinos of all flavors provide a flux…
We investigate the flux of supernova relic neutrinos (SRN) for several neutrino oscillation models with parameters inferred from recent experimental results. In the calculation, we adopt the realistic {\it time-dependent} supernova density…
The emission of $\MeV$-mass tau neutrinos from newly formed neutron stars is considered in a simple, but accurate, model based upon the diffusion approximation. The tau-neutrinosphere temperature is found to increase with mass so that…
Assuming a type-I seesaw mechanism for neutrino mass generation and invoking a baryogengesis via leptogenesis scenario, we consider a reasonable hierarchical structure for Dirac neutrino mass matrix, similar to up-type quark mass matrix.…
In a nuclear medium, spin-dependent forces cause the nucleon spins to fluctuate with a rate $\Gamma_\sigma$. We have previously shown that as a consequence the effective axial-current neutrino-nucleon scattering cross section is reduced.…
We explore the energy and entropy transport as well as the lepton number variation induced from the mixing between electron and sterile neutrinos with keV mass in the supernova core. We develop a radial- and time-dependent treatment of the…
The three Standard Model neutrinos can have Majorana mass or strictly Dirac mass, but both scenarios are practically indistinguishable in neutrino oscillation experiments. If they are pseudo-Dirac, however, there will be new mass splittings…
A Dirac quantum spin liquid hosts Dirac spinons, which are low-energy fractionalized neutral quasiparticles with spin 1/2 that obey the Dirac equation. Recent inelastic neutron scattering studies have revealed a cone spin continuum in…
Neutrinos may be pseudo-Dirac states, such that each generation is actually composed of two maximally-mixed Majorana neutrinos separated by a tiny mass difference. The usual active neutrino oscillation phenomenology would be unaltered if…
The effect of nonlinear self-interaction can be associated with superluminal velocity of neutrino. The power energy spectrum E=p+Cp^a is derived from the nonlinear Dirac equation when interaction term V=\lambda (\psi \gamma_\mu \psi \psi…
We examine constraints on a simple neutrino model in which there are three massless and three massive Dirac neutrinos and in which the left handed neutrinos are linear combinations of doublet and singlet neutrinos. We examine constraints…
Supernova 1987A offers a unique opportunity to study an evolving supernova in unprecedented detail over several decades. The X-ray emission is dominated by interactions between the ejecta and the circumstellar medium, primarily the…
We calculate limits on the properties of neutrinos using data from gamma-ray detectors on the Pioneer Venus Orbiter and Solar Max Mission satellites. A massive neutrino decaying in flight from the supernova would produce gamma rays…
Young pulsars are known to exhibit large space velocities, up to $10^3$ km/s. We propose a new mechanism for the generation of these large velocities based on an asymmetric emission of neutrinos during the supernova explosion. The mechanism…
We analyze the 1496 days of SuperKamiokande data to put limits on the nue, anti-nue, numu + nutau and anti-numu + anti-nutau components of the diffuse flux of supernova neutrinos, in different energy intervals and for different neutrino…