相关论文: Beryllium isotopic composition and Galactic cosmic…
Most of the previous studies on beryllium abundances in metal-poor stars have taken different Galactic populations as a whole when investigating the production and evolution of Be. In this Letter, we report on the detection of systematic…
We consider the effects of uncertainties in nuclear reaction rates on the cosmological constraints on the decays of unstable particles during or after Big-Bang nucleosynthesis (BBN). We identify the nuclear reactions due to non-thermal…
Standard Big Bang Nucleosynthesis at the baryon density determined by the microwave anisotropy spectrum predicts an excess of \li7 compared to observations by a factor of 4-5. In contrast, BBN predictions for D/H are somewhat below (but…
The standard model of cosmic ray propagation has been very successful in explaining all kinds of the Galactic cosmic ray spectra. However, high precision measurement recently revealed the appreciable discrepancy between data and model…
Determining the spatial distribution of Galactic cosmic rays (CRs) is fundamental to understand how these particles propagate in interstellar space and to infer their source spectra. The most sensitive method of studying this problem is…
Within the first 20 minutes of the evolution of the hot, dense, early Universe, astrophysically interesting abundances of deuterium, helium-3, helium-4, and lithium-7 were synthesized by the cosmic nuclear reactor. The primordial abundances…
This article aims at establishing new benchmark scenarios for Galactic cosmic-ray propagation in the GV-TV rigidity range, based on fits to the AMS-02 B/C data with the USINE v3.5 propagation code. We employ a new fitting procedure,…
We consider the role of diffusion in the redistribution of elements in the hot interstellar medium (ISM) of early-type galaxies. It is well known that gravitational sedimentation can affect significantly the abundances of helium and heavy…
The Earth's density distribution can be approximately considered piecewise continuous at the scale of two-flavor oscillations of typical solar neutrinos, such as the beryllium-7 and boron-8 neutrinos. This quite general assumption appears…
The propagation of charged particles, including cosmic rays, in a partially ordered magnetic field is characterized by a diffusion tensor whose components depend on the particle's Larmor radius $R_L$ and the degree of order in the magnetic…
Identifying the nucleosynthesis processes behind heavy-element enrichment in stellar atmospheres is challenging. It typically relies on comparing observed abundance-to-iron ratios with theoretical predictions relative to the Sun, but this…
An extensive program for the calculation of galactic cosmic-ray propagation has been developed. Primary and secondary nucleons, primary and secondary electrons, and secondary positrons are included. The basic spatial propagation mechanisms…
The primordial abundances of deuterium and of helium-3, produced during big bang nucleosynthesis, depend sensitively on the baryon density. Thus, the observed abundances of D and \he may provide useful ``baryometers'' provided the evolution…
We investigate lithium depletion in standard stellar models (SSMs) and main sequence (MS) open clusters, and explore the origin of the Li dispersion in young, cool stars of equal mass, age and composition. We first demonstrate that SSMs…
We explore further the proposal in paper I of this series that the confinement time of cosmic ray nuclei in the Milky Way is determined by their interaction with dark matter molecular clouds rather than by their escape from the halo, as is…
Using cosmic-ray boron to carbon ratio (B/C) data recently released by the AMS-02 experiment, we find tantalizing indications ({\it decisive evidence}, in Bayesian terms) in favor of a diffusive origin for the broken power-law spectra found…
Context: Features in the spectra of primary cosmic rays (CRs) provide invaluable information on the propagation of these particles in the Galaxy. In the rigidity region around a few hundred GV, such features have been measured in the proton…
Heavy particles in galaxy clusters tend to be more centrally concentrated than light ones according to the Boltzmann distribution. An estimate of the drift velocity suggests that it is possible that the helium nuclei may have entirely or…
The abundance of beryllium in the oldest, most metal-poor stars acts as a probe of early star formation and Galactic chemical evolution. We have analyzed high-resolution, high signal-to-noise Keck/HIRES spectra of 24 stars with [Fe/H] from…
The vertical diffusive halo size of the Galaxy, $L$, is a key parameter for dark matter indirect searches. It can be better determined thanks to recent AMS-02 data. We set constraints on $L$ from Be/B and $^{10}$Be/Be data, and we performed…