178 citations · 726 across the 27 of their papers we have counts for
23 papers · 1 filter
Dynamic Competition of Fast and Collisional Neutrino Flavor Instabilities with Collisional Damping in Spatially Inhomogeneous Systems
Shota Takahashi, Hiroki Nagakura, Masamichi Zaizen +2
Neutrino flavor evolution in dense astrophysical environments such as core-collapse supernova (CCSN) is influenced by collective effects. While the Fast Flavor Instability (FFI) an…
Fast Neutrino-Flavor Conversion with Attenuation and Global Lepton Gradient
Masamichi Zaizen, Hiroki Nagakura
Fast neutrino-flavor conversion (FFC) can nontrivially alter neutrino radiation field in core-collapase supernovae (CCSN) and binary neutron-star merger (BNSM) remnants. However, i…
Dynamical equilibria of fast neutrino flavor conversion
Jiabao Liu, Lucas Johns, Hiroki Nagakura +2
Dense neutrino systems, which display collectivity mediated by the weak interaction, have deep parallels with mean-field kinetic systems governed by other fundamental forces. We id…
Observing Supernova Neutrino Light Curves with Super-Kamiokande.VI. A Practical Data Analysis Technique Considering Realistic Experimental Backgrounds
Fumi Nakanishi, Ken'ichiro Nakazato, Masayuki Harada +9
Neutrinos from supernovae, especially those emitted during the late phase of core collapse, are essential for understanding the final stages of massive star evolution. We have been…
Neutrino Constraints on Black Hole Formation in M31
Yudai Suwa, Ryuichiro Akaho, Yosuke Ashida +9
We investigate neutrino signals associated with black hole formation resulting from the gravitational collapse of massive stars, motivated by the candidate failed supernova M31-201…
Asymptotic states of fast neutrino-flavor conversions in the three-flavor framework
Jiabao Liu, Hiroki Nagakura, Masamichi Zaizen +2
There has been growing evidence that mu and tau neutrinos are noticeably different due to the emergence of muons in core-collapse supernovae (CCSNe) and binary neutron star mergers…
Resolution requirements for numerical modeling of neutrino quantum kinetics
Hiroki Nagakura, Masamichi Zaizen, Jiabao Liu +1
Neutrino quantum kinetics is a rapidly evolving field in computational astrophysics, with a primary focus on collective neutrino oscillations in core-collapse supernovae and post-m…
Quasi-steady evolution of fast neutrino-flavor conversions
Jiabao Liu, Hiroki Nagakura, Masamichi Zaizen +3
In astrophysical environments such as core-collapse supernovae (CCSNe) and binary neutron star mergers (BNSMs), neutrinos potentially experience substantial flavor mixing due to th…
Inspecting neutrino flavor instabilities during proto-neutron star cooling phase in supernova: I. Spherically symmetric model
Masamichi Zaizen, Sherwood Richers, Hiroki Nagakura +2
In the standard model of core-collapse supernova (CCSN), all neutrinos are assumed to be in pure flavor eigenstates in CCSN cores, but the assumption becomes invalid if neutrino di…
BGK subgrid model for neutrino quantum kinetics
Hiroki Nagakura, Lucas Johns, Masamichi Zaizen
We present a new subgrid model for neutrino quantum kinetics, which is primarily designed to incorporate effects of collective neutrino oscillations into neutrino-radiation-hydrody…
Universality of the Neutrino Collisional Flavor Instability in Core Collapse Supernovae
Jiabao Liu, Hiroki Nagakura, Ryuichiro Akaho +3
Neutrinos are known to undergo flavor conversion processes among the three flavors. The fast flavor conversion (FFC) has been the central piece of flavor conversions taking place i…
Fast neutrino-flavor swap in high-energy astrophysical environments
Masamichi Zaizen, Hiroki Nagakura
We assert that non-linear features of fast neutrino-flavor conversion (FFC) can be qualitatively different between core-collapse supernovae (CCSNe) and binary neutron star mergers…
Collisional and Fast Neutrino Flavor Instabilities in Two-dimensional Core-collapse Supernova Simulation with Boltzmann Neutrino Transport
Ryuichiro Akaho, Jiabao Liu, Hiroki Nagakura +2
We present a comprehensive study on the occurrences of the collisional flavor instability (CFI) and the fast flavor instability (FFI) of neutrinos based on a two-dimensional (2D) c…
Basic characteristics of neutrino flavor conversions in the post-shock regions of core-collapse supernova
Hiroki Nagakura, Masamichi Zaizen
One of the active debates in core-collapse supernova (CCSN) theory is how significantly neutrino flavor conversions induced by neutrino-neutrino self-interactions change the conven…
Characterizing quasi-steady states of fast neutrino-flavor conversion by stability and conservation laws
Masamichi Zaizen, Hiroki Nagakura
The question of what ingredients characterize the quasi-steady state of fast neutrino-flavor conversion (FFC) is one of the long-standing riddles in neutrino oscillation. Addressin…
Flavor conversions with energy-dependent neutrino emission and absorption
Chinami Kato, Hiroki Nagakura, Masamichi Zaizen
Fast neutrino flavor conversions (FFCs) and collisional flavor instabilities (CFIs) potentially affect the dynamics of core-collapse supernovae (CCSNe) and binary neutron star merg…
Simple method for determining asymptotic states of fast neutrino-flavor conversion
Masamichi Zaizen, Hiroki Nagakura
Neutrino-neutrino forward scatterings potentially induce collective neutrino oscillation in dense neutrino gases in astrophysical sites such as core-collapse supernovae (CCSN) and…
Connecting small-scale to large-scale structures of fast neutrino-flavor conversion
Hiroki Nagakura, Masamichi Zaizen
We present a systematic study of fast neutrino-flavor conversion (FFC) with both small-scale and large-scale numerical simulations in spherical symmetry. We find that FFCs can, in…
Time-dependent and quasi-steady features of fast neutrino-flavor conversion
Hiroki Nagakura, Masamichi Zaizen
Despite the theoretical indication that fast neutrino-flavor conversion (FFC) ubiquitously occurs in core-collapse supernova and binary neutron star merger, the lack of global simu…
Code Comparison for Fast Flavor Instability Simulation
Sherwood Richers, Huaiyu Duan, Meng-Ru Wu +5
The fast flavor instability (FFI) is expected to be ubiquitous in core-collapse supernovae and neutron star mergers. It rapidly shuffles neutrino flavor in a way that could impact…
Three-flavor collective neutrino conversions with multi-azimuthal-angle instability in an electron-capture supernova model
Masamichi Zaizen, Shunsaku Horiuchi, Tomoya Takiwaki +4
We investigate the multi-azimuthal angle (MAA) effect on collective neutrino oscillation by considering the three-dimensional neutrino momentum distribution in a realistic electron…
Neutrino halo effect on collective neutrino oscillation in iron core-collapse supernova model of a 9.6 star
Masamichi Zaizen, John F. Cherry, Tomoya Takiwaki +4
We extend the multi-angle computational framework and investigate the time evolution of the neutrino halo on collective neutrino oscillation in the core collapse of an iron core pr…
Collective neutrino oscillations and detectabilities in failed supernovae
Masamichi Zaizen, Takashi Yoshida, Kohsuke Sumiyoshi +1
We investigate the collective neutrino oscillations under the three flavor multi-angle approximation in a spherically symmetric simulation of failed supernovae. A failed supernova…