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Extremely low background experiments to measure key nuclear reaction cross sections of astrophysical interest are conducted at the world's deepest underground laboratory, the Jingping Underground laboratory for Nuclear Astrophysics (JUNA). High precision measurements provide reliable information to understand nucleosynthetic processes in celestial objects and resolve mysteries on the origin of atomic nuclei discovered in the first generations of Pop. III stars in the universe and meteoritic SiC grains in the solar system., 5 pages, 2 figures

We investigate the neutrino flavor change effects due to neutrino self-interaction and shock wave propagation, as well as the matter effects on the neutrino process in core-collapsing supernovae (CCSNe). For the hydrodynamics, we use two models: a simple thermal bomb model and a specified hydrodynamics model for SN1987A. For the presupernova model, we take an updated model, adjusted to explain SN1987A, which employs recent developments in the (n, γ) reaction rates for nuclei near the stability line (A ∼ 100). As for the neutrino luminosity, we adopt two different models: equivalent neutrino luminosity and nonequivalent luminosity models. The latter is taken from a synthetic analysis of CCSN simulation data, which quantitatively presented the results obtained by various neutrino transport models. Relevant neutrino-induced reaction rates are calculated using a shell model for light nuclei and a quasiparticle random phase approximation model for heavy nuclei. For each model, we present abundances of the light nuclei (7Li, 7Be, 11B, and 11C) and the heavy nuclei (92Nb, 98Tc, 138La, and 180Ta) produced by the neutrino process. The light nuclei abundances turn out to be sensitive to the Mikheyev–Smirnov–Wolfenstein (MSW) region around O-Ne-Mg layer while the heavy nuclei are mainly produced prior to the MSW region. Through detailed analyses, we find that neutrino self-interaction becomes a key ingredient, in addition to the MSW effect, for understanding the neutrino process and the relevant nuclear abundances. The normal mass hierarchy is shown to be more compatible with the meteorite data. The main nuclear reactions for each nucleus are also investigated in detail.

We explore photon vortex generation in synchrotron radiations from a spiral moving electron under a uniform magnetic field along z-axis using Landau quantization. The obtained wave-function of the photon vortices is the eigen-state of the z-component of the total angular momentum (zTAM). In m-th harmonic radiations, individual photons are the eigen-state of zTAM of mħ. This is consistent with previous studies. Using the presently obtained wave-functions we calculate the decay widths and the energy spectra under extremely strong magnetic fields of 1012–1013 G, which are observed in astrophysical objects such as magnetized neutron stars and jets and accretion disks around black holes. The result suggests that photon vortices are predominantly generated in such objects. Although they have no coherency it is expected that photon vortices from the universe are measured using a detector based upon a quantum effect in future. This effect also affects to stellar nucleosynthesis in strong magnetic fields.

Nuclear astrophysics is an interdisciplinary research field of nuclear physics and astrophysics, seeking for the answer to a question, how to understand the evolution of the Universe with the nuclear processes which we learn. We review the research activities of nuclear astrophysics in east and southeast Asia which includes astronomy, experimental and theoretical nuclear physics and astrophysics. Several hot topics such as the Li problems, critical nuclear reactions and properties in stars, properties of dense matter, r-process nucleosynthesis and $\nu$-process nucleosynthesis are chosen and discussed in further details. Some future Asian facilities, together with physics perspectives, are introduced., Comment: 49 pages, 10 figures, published in AAPPS (Association of Asia Pacific Physical Societies) Bulletin

The discovery of amino acids in meteorites has presented two clues to the origin of their processing subsequent to their formation: a slight preference for left-handedness in some of them, and isotopic anomalies in some of their constituent atoms. In this article we present theoretical results from the Supernova Neutrino Amino Acid Processing (SNAAP) model, which uses electron anti-neutrinos and the magnetic fields from source objects such as supernovae or colliding neutron stars to selectively destroy one amino acid chirality and to create isotopic abundance shifts. For plausible magnetic fields and electron anti-neutrino fluxes, non-zero, positive enantiomeric excesses, $ee$s, defined to be the relative left/right asymmetry in an amino acid population, are reviewed for two amino acids, and conditions are suggested that would produce $ee>0$ for all of the $\alpha$-amino acids. The relatively high energy anti-neutrinos that produce the $ee$s would inevitably also produce isotopic anomalies. A nuclear reaction network was developed to describe the reactions resulting from them and the nuclides in the meteorites. At similar anti-neutrino fluxes, assumed recombination of the detritus from the anti-neutrino interactions is shown to produce appreciable isotopic anomalies in qualitative agreement with those observed for D/$^1$H and $^{15}$N/$^{14}$N. The isotopic anomalies for $^{13}$C/$^{12}$C are predicted to be small, as are also observed. Autocatalysis may be necessary for any model to produce the largest $ee$s observed in meteorites. This allows the constraints of the original SNAAP model to be relaxed, increasing the probability of meteoroid survival in sites where amino acid processing is possible. These results have obvious implications for the origin of life on Earth., Comment: 24 pages, 8 figures, to be published in Physical Review Research

We study the evolution of rapid neutron-capture process (r-process) isotopes in the galaxy. We analyze relative contributions from core-collapse supernovae (CCSNe), neutron star mergers, and collapsars under a range of astrophysical conditions and nuclear input data. Here we show that, although the r-process in each of these sites can lead to a similar (universal) elemental distribution, the detailed isotopic abundances can differ from one site to another. These differences may allow for the identification of which sources contributed to the early evolution of r-process material in the galaxy. Our simulations suggest that the early evolution was dominated by CCSNe and collapsar r-process nucleosynthesis. This conclusion may be testable if the next generation of observatories can deduce isotopic r-process abundances.

A $\ensuremath{\beta}$-decay unstable isomer with a half-life of 14.1 yr at 264 keV in $^{113}\mathrm{Cd}$ is a branching point in the $s$ process, from which a weak branch reaches to a rare tin isotope $^{115}\mathrm{Sn}$ whose astrophysical origin has been an open problem. We have measured $\ensuremath{\gamma}$ rays decaying to the ground state or the isomer in the $^{112}\mathrm{Cd}(n,\ensuremath{\gamma})^{113}\mathrm{Cd}$ reaction using high-energy resolution detectors in conjunction with a time-of-flight method. The relative production ratios of the isomer to the total following the neutron capture reactions on $^{112}\mathrm{Cd}$ have been evaluated in an energy region of up to 9 keV, and the spin and parity of several resonances have been assigned.

We study dynamical screening effects of nuclear charge on big bang nucleosynthesis (BBN). A moving ion in plasma creates a distorted electric potential leading to a screening effect which is different from the standard static Salpeter formula. We consider the electric potential for a moving test charge, taking into account dielectric permittivity in the unmagnetized Maxwellian plasma during the BBN epoch. Based on the permittivity in a BBN plasma condition, we present the Coulomb potential for a moving nucleus, and show that enhancement factor for the screening of the potential increases the thermonuclear reaction rates by a factor order of 10^(-7). In the Gamow energy region for nuclear collisions, we find that the contribution of the dynamical screening is less than that of the static screening case, consequently which primordial abundances hardly change. Based on the effects of dynamical screening under various possible astrophysical conditions, we discuss related plasma properties required for possible changes of the thermal nuclear reactions.

We study neutrino and antineutrino emission from the direct Urca process in neutron-star matter in the presence of strong magnetic fields. We calculate the neutrino emissivity of the direct Urca process, whereby a neutron converts to a proton, an electron and an antineutrino, or a proton-electron pair converts to a neutron-neutrino pair. We solve exact wave functions for protons and electrons in the states described with Landau levels. We find that the direct Urca process can satisfy the kinematic constraints even in density regions where this process could not normally occur in the absence of a magnetic field., Comment: 15 pages, 5 figures

For the first time in an application to nuclear astrophysics, a process induced by the unstable $$^5$$ He = ( $$^4$$ He-n) nucleus, the $$^3$$ He+ $$^5$$ He $$\rightarrow $$ 2 $$\alpha $$ reaction, has been studied through the Trojan Horse Method (THM). For that purpose, the quasi-free (QF) contribution of the $$^9$$ Be( $$^3$$ He, $$\alpha \alpha $$ ) $$^4$$ He reaction was selected at $$E_{^{3}\text{ He }}=4$$ MeV incident energy. The reaction was studied in a kinematically complete experiment following a recent publication (Spitaleri et al. in Eur Phys J A 56:18, 2020), where for the quasi free contribution the momentum distribution between $$\alpha $$ and $$^5$$ He particle cluster in the $$^9$$ Be nucleus in the ground state have been extracted. The angular distribution of the QF $$^3$$ He+ $$^5$$ He $$\rightarrow $$ 2 $$\alpha $$ reaction was measured at $$\theta _{cm}$$ = 78 $$^{\circ }$$ –115 $$^{\circ }$$ . The energy dependence of the differential cross section of the $$^3$$ He+ $$^5$$ He $$ \rightarrow $$ 2 $$\alpha $$ virtual reaction was extracted in the energy range $$E_{cm}$$ = 0–650 keV. The total cross section obtained from the Trojan-horse method was normalized to absolute cross sections from a theoretical calculation in the energy range $$E_{cm}$$ =300–620 keV.

We study the photodisintegration process triggered by the nonthermal electromagnetic Hawking radiation from primordial black holes (PBHs) in critical collapse model. We consider the simplest case that all PBHs formed at a single epoch stemming from an inflationary spectrum with a narrow peak, and an extended mass distribution is obtained due to critical phenomena of gravitational collapse. The presence of a low-mass tail of critical collapse mass function could lead to an enhancement of energetic photon emissions from Hawking radiation of PBHs. Nuclear photodisintegration rates are calculated with a nonthermal photon spectrum derived by solving the Boltzmann equation iteratively. The exact spectrum is much different than that based on an often-used analytical bended power-law spectrum and it is found to significantly depend on the adopted PBH mass functions. With the newest observational limit on the $^3$He abundance in Galactic H II regions, the updated $^3$He constraints on PBH mass spectrum in the horizon mass range $10^{12} - 10^{13}$ g are derived. Our results for the first time show that $^3$He constraints on the critical mass function are about one order of magnitude severer than the monochromatic one although the fraction of PBHs in the low-mass tail region is relatively small. The $^6$Li elemental abundance is also enhanced significantly for the critical mass function. More precise measurement of $^6$Li abundance is highly desirable to provide a promising constraint on PBHs in the future. For monochromatic mass function, we provide the analytical bounds for photodisintegration and hadrodissociation from PBH radiation, and we report discrepancies between our updated $^3$He constraints and the previous results., 38 pages, 14 figures, Accepted for JCAP

A new thermonuclear $^{17}$O($n$,$\gamma$)$^{18}$O rate is derived based on a complete calculation of the direct-capture (DC) and resonant-capture contributions, for a temperature region up to 2 GK of astrophysical interest. We have firstly calculated the DC and subthreshold contributions in the energy region up to 1 MeV, and estimated the associated uncertainties by a Monte-Carlo approach. It shows that the present rate is remarkably larger than that adopted in the JINA REACLIB in the temperature region of 0.01 $\sim$ 2 GK, by up to a factor of $\sim$80. The astrophysical impacts of our rate have been examined in both $s$-process and $r$-process models. In our main $s$-process model which simulates flash-driven convective mixing in metal deficient asymptotic giant branch stars, both $^{18}$O and $^{19}$F abundances in interpulse phases are enhanced dramatically by factors of $\sim 20$--$40$ due to the new larger $^{17}$O($n$,$\gamma$)$^{18}$O rate. It shows, however, that this reaction hardly affects the weak $s$-process in massive stars since the $^{17}$O abundance never becomes significantly large in the massive stars. For the $r$-process nucleosynthesis, we have studied impacts of our rate in both the collapsar and neutron burst models, and found that the effect can be neglected, although an interesting "loophole" effect is found owing to the enhanced new rate, which significantly changes the final nuclear abundances if fission recycling is not involved in the model, however, these significant differences are almost completely washed out if the fission recycling is considered., Comment: 27 pages, 28 figures

Measurements of the isotopic abundances in meteoritic amino acids have found enhancements of $^2$H/H, $^{15}$N/$^{14}$N, and $^{13}$C/$^{12}$C in the amino acids in the meteorites studied. We show that they are consistent with the processing of the constituents of the meteorites by electron anti-neutrinos that would be expected from a core-collapse supernova or neutron-star merger. Using theoretical electron anti-neutrino cross sections we are able to predict these isotopic ratio variations depending on the time-integrated anti-neutrino flux at the site where the amino acids were processed.

We have proposed a short-lived radioisotope 98Tc as the nuclear cosmochronometer to evaluate the time from the last supernova neutirno-process to the solar system formation (SSF). We have calculated the supernova neutirno-process using a SN 1987A model with neutrino-induced reaction cross sections. The calculated result is consistent with the observed upper limit of 98Tc/98Ru at the SSF.

We have updated nuclear weak rates relevant to the study of astrophysical processes in stars. Neutrino-induced reaction cross sections, electron-capture and β-decay rates at stellar environments are obtained with new shell-model Hamiltonians that prove to be successful in describing spin responses — Gamow-Teller and spin-dipole transitions — in nuclei. The cross sections and rates are applied to nucleosynthesis in supernovae, detection of ν and nuclear URCA processes.

The neutrino process ($\nu$-process) for the production of 7Li and 11B in core-collapse supernovae (SNe) is extensively investigated. Initial abundances of s-nuclei and other physical conditions are derived from an updated calculation of the SN 1987A progenitor. The nuclear reaction network including neutrino reactions is constructed with the variable order Bader-Deuflhard integration method. We find that yields of 7Li and 11B significantly depend on the stellar metallicity while they are independent of the weak s-process during the stellar evolution. When the metallicity is high, there are more neutron absorbers, i.e., 56Fe, 14N (from initial CNO nuclei), and 54Fe, and the neutron abundance is small during the $\nu$-process. Since 7Be is predominantly destroyed via 7Be(n,p)7Li, a change in the neutron abundance results in different 7Be yields. Then, the calculated yield ratio 7Li/11B=0.93 for the solar metallicity is larger than that for the SN 1987A 7Li/11B=0.80 by 16 % in the inverted mass hierarchy case. We analyze contributions of respective reactions as well as abundance evolution, and clarify the $\nu$-process of 7Li and 11B.

We calculate the abundances of 7Li, 11B, 92Nb, 98Tc, 138La, and 180Ta produced by neutrino (ν)-induced reactions in a core-collapse supernova explosion. We consider the modification by ν self-interaction (ν-SI) near the neutrinosphere and the Mikheyev–Smirnov–Wolfenstein (MSW) effect in the outer layers based on time-dependent neutrino energy spectra. Abundances of 7Li and the heavy isotopes 92Nb, 98Tc, and 138La are reduced by a factor of 1.5–2.0 by the ν-SI. In contrast, 11B is relatively insensitive to the ν-SI. We find that the abundance ratio of heavy to light nuclei, 138La/11B, is sensitive to the neutrino mass hierarchy, and the normal mass hierarchy is more likely to be consistent with the solar meteoritic abundances.

We explore screening effects arising from a relativistic magnetized plasma with applications to Big Bang nucleosynthesis (BBN). %Specifically, due to their small magnetic moments, energies of electrons and positrons can be easily quantized via Landau quantization. The screening potential which depends on the thermodynamics of charged particles in the plasma is altered by the magnetic field. We focus on the impact of screening on the electron capture interaction. Taking into account the correction in BBN arising from a homogeneous primordial magnetic field (PMF), we constrain the epoch at which the PMF was generated and its strength during BBN. Considering such screening corrections to the electron capture rates and using up-to-date observations of primordial elemental abundances, we also discuss the possibility of solving the problem of under-estimation of the deuterium abundance. We find for certain values of the PMF strength predicted D and $^4$He abundances are both consistent with the observational constraints., 18 pages, 7 figures, submitted to Phys. ReV. D

The discovery of bio-molecules in meteorites with an excess of one chiral state has created one of the biggest questions in astrobiology today. That is, what is the origin of bio-molecular homochirality? Studies of this question are highly interdisciplinary, and while several phenomenological models exist, we examine the relationship between fundamental symmetries at the particle level and the macroscopic formation of bio-molecules. A model has been developed which couples fundamental interactions with the formation of molecular chirality. In this magneto-chiral model atomic nuclei bound in amino acids interact via the weak interaction in stellar environments. Nuclei are coupled to the molecular geometry (chirality) via the shielding tensor, the same interaction responsible for NMR identification. Associated with this is the fact that isotopic abundances vary from solar system values. Interactions with leptons can selectively destroy one chiral state over the other while changing isotopic values. Possible sites are proposed in which this model may exist.

For searching beyond Standard Model physics, stars are laboratories which complement terrestrial experiments. Massless neutrinos in the Standard Model of particle physics cannot have a magnetic moment, but massive neutrinos have a finite magnetic moment in the minimal extension of the Standard Model. Large extra dimensions are a possible solution of the hierarchy problem. Both of these provide additional energy loss channels in stellar interiors via the electromagnetic interaction and radiation into extra dimensions, respectively, and thus affect stellar evolution. We perform simulations of stellar evolution with such additional energy losses and find that they eliminate the blue loops in the evolution of intermediate-mass stars. The existence of Cepheid stars can be used to constrain the neutrino magnetic moment and large extra dimensions. In order for Cepheids to exist, the neutrino magnetic moment should be smaller than the range ~2x10^{-10} to 4x10^{-11}mu_B, where mu_B is the Bohr magneton, and the fundamental scale in the (4+2)-spacetime should be larger than ~2 to 5 TeV, depending on the rate of the ^{12}C(alpha, gamma)^{16}O reaction. The fundamental scale also has strong dependence on the metallicity. This value of the magnetic moment is in the range explored in the reactor experiments, but higher than the limit inferred from globular clusters. Similarly the fundamental scale value we constrain corresponds to a size of the compactified dimensions comparable to those explored in the torsion balance experiments, but is smaller than the limits inferred from collider experiments and low-mass stars., Comment: 12 pages, 14 figures, accepted for publication in ApJ

Since 7Li is easily destroyed in low temperatures, the surface lithium abundance decreases as stars evolve. This is supported by the lithium depletion observed in the atmosphere of most red giants. However, recent studies show that almost all of red clump stars have high lithium abundances A(Li)>-0.9, which are not predicted by the standard theory of the low-mass stellar evolution. In order to reconcile the discrepancy between the observations and the model, we consider additional energy loss channels which may come from physics beyond the Standard Model. A(Li) slightly increases near the tip of the red giant branch even in the standard model with thermohaline mixing because of the 7Be production by the Cameron-Fowler mechanism, but the resultant 7Li abundance is much lower than the observed values. We find that the production of 7Be becomes more active if there are additional energy loss channels, because themohaline mixing becomes more efficient and a heavier helium core is formed., 8 pages, 11 figures, accepted by MNRAS