Conveners
Oral Presentation: Session 1
- Masakiyo Kitazawa (YITP, Kyoto University)
Oral Presentation: Session 2
- Toru Tamagawa (RIKEN)
Oral Presentation: Session 3
- Nobuya Nishimura (The University of Tokyo)
Oral Presentation: Session 4
- Nobuya Nishimura (The University of Tokyo)
Oral Presentation: Session 5
- Tomoya Naito (RIKEN iTHEMS)
Oral Presentation: Session 6
- Nils Paar (Faculty of Science University of Zagreb)
Oral Presentation: Session 7
- Nils Paar (Faculty of Science University of Zagreb)
Oral Presentation: Session 8
- Hidetoshi Yamaguchi (Center for Nuclear Study, the University of Tokyo)
Oral Presentation: Session 9
- Hidetoshi Yamaguchi (Center for Nuclear Study, the University of Tokyo)
Oral Presentation: Session 10
- Eiji Kido (Institute for Cosmic Ray Research, University of Tokyo)
Oral Presentation: Session 11
- Eiji Kido (Institute for Cosmic Ray Research, University of Tokyo)
Oral Presentation: Session 12
- Akira Dohi (RIKEN)
Oral Presentation: Session 13
- Akira Dohi (RIKEN)
It depends on the allocated time for the talk, but generally I plan to review recent developments in 3D neutrino / hydrodynamics simulations related to questions of minimum neutron star mass / fall back supernova / neutron star birth spin etc.
Systematic studies of core-collapse supernovae (CCSNe) have been conducted based on hundreds of one-dimensional artificial models (O'Connor & Ott 2011,2013; Ugliano et al. 2013, Ertl et al. 2015) and two-dimensional self-consistent simulations (Nakamura et al. 2015;2019, Burrows & Vartanyan 2020). We have performed three-dimensional magnetohydrodynamic simulations for the core-collapse of 16...
Chiral plasmas may exist in supernovae and neutron stars. We will discuss the unique instabilities inherent to chiral plasmas, with particular focus on a few newly found ones inclding the chiral magnetovortical instability, chiral Hall instability, and viscosity-induced instability. We will explore the potential implications of these instabilities in supernova and neutron star physics.
Various phases in dense matter, which may be realized in the inner core of neutron stars, have been investigated from viewpoints of nuclear and particle physics and astrophysics. In particular, strangeness degrees of freedom such as kaon condensates (KC) and hyperons (Y=$\Lambda$, $\Xi^-$, …) may appear in highly dense system. We have considered possible coexistence of KC and Y-mixed matter...
Supernova remnants (SNRs) are one of the key tools for understanding the SN explosion mechanism and enrichment of the universe. We have launched the X-ray satellite XRISM, which enables us to carry out excellent spectroscopy for extended sources such as SNRs. In this talk, we will summarize the recent progress on SNRs with XRISM.
Neutron stars are high-density objects remained after a supernova explosion, in which the entire star is likened to a single atomic nucleus. Due to their high density exceeding the density of the nuclear density, it has been discussed that states and particles that do not appear in a normal nucleus can appear inside a neutron star. The realisation of superfluid states of neutrons and protons,...
I will talk about how temperature observations of neutron stars provide a unique window to explore physics beyond the Standard Model of particle physics. The presence of hypothetical particles such as axions and dark matter, predicted by theories that extend the Standard Model, could alter the cooling behavior of the neutron stars. Axions, for example, increase cooling rates, while dark matter...
Theoretical evaluation of fusion reaction rates, critical in astrophysical phenomena, is essential because low-energy data, which are often difficult to measure directly, are required. This talk will discuss the effects of cluster resonances on 12C+12C and 12C+16O fusion reactions. Resonances drastically increase the cross section and thus can significantly impact the reaction rate....
Accreting neutron stars exhibit a broad range of nuclear reactions, from the rapid proton capture process in X-ray bursts at the surface to electron captures, neutron reactions, and fusion of neutron rich nuclei in the outer crust. These reactions give rise to a range of dynamic observables. At rare isotope beam facilities such as FRIB at MSU many of these reactions can now be studied. I will...
The LIGO-Virgo-KAGRA observation run 4 have found only a surprisingly small number of compact binary coalescences involving neutron stars. In this talk, I will discuss the current status and future prospects for multimessenger astronomy with neutron stars.
Heavy element synthesis within stellar bodies typically manifests in explosive
environments such as neutron star mergers. These potential sites present high
enough neutron densities that facilitate neutron degeneracy. In this work, we
study the effect of neutron degeneracy on stellar capture rates for nuclei ranging
from stability to the neutron drip line. We investigate how degeneracy can...
Nuclear processes in stellar environments, such as those occurring in core-collapse supernovae and neutron star mergers, occur at extremely high temperatures, ranging from millions to billions of kelvin. These conditions differ markedly from the zero-temperature limit typically assumed in traditional nuclear studies. In a recent study, we presented the first comprehensive mapping of nuclear...
Accounting for out-of-NSE (nuclear statistical equilibrium) r-process nucleosynthesis is one of the most sought-after goals in the (numerical) modelling of binary neutron star (BNS) mergers. While post-processing analysis via full nuclear networks is a reliable technique, the computational and storage costs prevent such calculations to be directly coupled to hydrodynamic codes, thus neglecting...
The pasta phases in the inner crust of neutron stars are crucial for understanding their behavior. However, simulating these phases using coordinate-space density functional theory is computationally expensive. In this contribution, we propose to perform such simulations effectively by the fermion operator expansion method. We apply this method to investigate the slab phases described by...
I will present new perspectives on the properties of matter at high baryon density and low temperatures with the application to the description of neutron stars in mind. In particular, I will discuss the role of QCD in constraining the equation of state and the possible duality in dense matter, known as Quarkyonic duality.
Neutron-star mergers are excellent laboratories for stuying the properties of high-density matter. I will report our recent study modeling the imprint of helium absorption features in kilonova spectra, which revealed that the kilonova accompanying GW170817 likely did not harbor significant amounts of helium. I will discuss the implications of this finding for the lifetime of the neutron-star...
$\beta$-decay half-life is sensitive to the shell structure near the Fermi levels. Nuclear deformation thus impacts the $\beta$-decay properties.
A first-order shape-phase transition in neutron-rich Zr isotopes is predicted by some models. We investigate the $\beta$-decay half-lives of neutron-rich nuclei around $^{110}$Zr, where the shape-phase transition is predicted to occur, to see if...
The range of applicability of nuclear ab initio calculations is expanding. Owing to developments in, for example, chiral effective field theory and renormalization group techniques, we are now able to obtain results that maintain a connection to the underlying theory of the strong interaction, quantum chromodynamics. By introducing a new storage scheme for the three-body matrix elements, we...
Understanding the strong nuclear force is fundamental to understanding the formation of matter in the Universe. Since Yukawa’s meson theory, the nuclear force has been formulated in terms of two-nucleon interactions. Three-nucleon forces (3NFs), which appear when more than two nucleons interact, have been revealed in the last two decades. The establishment of high-precision two-nucleon...
Since the discovery of the kilonova associated with GW170817, neutron star mergers have been regarded as astrophysical sites of the r-process nuclei. However, it remains a mystery how the robustness of the r-process patterns (or universality) in metal-poor stars can be explained. The mechanism that leads to high Th/Eu ratios (actinide boost) has not been well understood, either. In this talk,...
Pair-instability supernovae (PISNe) are the final fates of massive stars with an initial mass ranging from 140-260 $M_{\odot}$. Due to the efficient $^{56}\mathrm{Ni}$ nucleosynthesis, PISNe can be very luminous phenomena. According to some previous works, not only the PISN progenitor evolution but also the PISN nucleosynthesis is affected from $^{12}{\rm C}(\alpha,\gamma)^{16}{\rm O}\,$...
Neutron stars exhibit sudden changes of its rotational velocity, known as "pulsar glitches". It has been believed that glitches are mainly caused by superfluid neutron vortices in the inner crust of neutron stars. However, importance of contributions of the outer core has been recently discussed, and further microscopic investigations of quantum vortices and flux-tubes in the outer core of...
Clarifying origins and acceleration mechanisms of the most energetic particles in the universe has been the 100-year endeavor, being one of the most intriguing mysteries in an interdisciplinary research among astroparticle physics, high-energy physics and nuclear physics. Since ultrahigh-energy cosmic rays (UHECRs) are deflected less strongly by the Galactic and extra-galactic magnetic fields...
Current observations of arrival directions of ultra-high energy cosmic rays (UHECR) whose energies are above 100 EeV do not show significant anisotropy. To explain this situation, we may assume higher source density, heavier mass composition of UHECR, or stronger magnetic fields.
Recently the idea of super-heavy UHECR (r-process nuclei like uranium) has been suggested G. Farrar 2024, B.T....
New Views on Thermonuclear Bursts
Long X-ray bursts (XRBs) are rare events, which are only <1% of ordinary XRBs.
Although long XRBs as well as ordinary XRBs are interpreted as thermonuclear
runaway on neutron stars, their fuel or ignition conditions are still open to debate.
In addition, there are some observations which indicate interactions between bursts
and accretion disks. This talk will summarize recent observations...
X-ray bursts are frequently observed thermonuclear explosion events in the universe. Understanding their light curves is crucial for unveiling the properties of neutron stars. The shape of the light curve is sensitive to various nuclear reaction rates. It has been shown that the 59Cu(p,γ)60Zn and 59Cu(p,α)56Ni reaction rates have the most significant impact on the light curve. These reactions...
Analyzing the current cosmic elemental composition opens the door to the origin of the cosmic elements. This requires a detailed analysis of the r-processes nucleosynthesis. Among them, our research is aimed at obtaining information on the fission of neutron-rich nuclei in the heavy and superheavy mass regions [1]. Fission fragments of neutron-rich nuclei in the superheavy elemental regions...
Photon vortices are light that carry large orbital angular momentum (OAM) in quantum level [1]. They can be described by Laguerre-Gaussian or Bessel wavefunctions, which are waves being the eigenstates of the distinct angular momentum along their propagation direction . Unlike plane-wave photons, photon vortices interact differently with materials because their OAM changes the process where...
