Related papers: New Experimentally Observable Gamma-ray Emissions …
Background:The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Reduce the $^{243}$Am(n,$\gamma$) cross section uncertainty. Method: The…
For the first time, we use the Gamma-ray Burst Monitor (GBM) on-board the Fermi satellite to search for sterile neutrino decay lines in the energy range 10-25 keV corresponding to sterile neutrino mass range 20-50 keV. This energy range has…
De-excitation gamma-ray lines, produced by nuclei colliding with protons, provide information about astrophysical environments where particles have kinetic energies of $10-100$ MeV per nucleon. In general, such environments can be…
We report the result of a search for the rare decay B^0 -> gamma gamma in 426 fb-1 of data, corresponding to 226 million B^0 \bar{B}^0 pairs, collected on the Upsilon(4S) resonance at the PEP-II asymmetric-energy e+e- collider using the…
As pointed out by Lingenfelter and Ramaty (1977), the shapes of some gamma-ray lines produced by cosmic-ray interactions with the interstellar medium potentially contain valuable information on the physical properties of dust grains,…
The nucleosynthesis in classical novae, in particular that of radioactive isotopes, is directly measurable by its $\gamma$-ray signature. Despite decades of observations, MeV $\gamma$-rays from novae have never been detected -- neither…
Recently some hints of the existence of $\gamma$-ray line around 130 GeV are reported according to the analysis of Fermi-LAT data. If confirmed it would be the first direct evidence to show the existence of new physics beyond the standard…
A compact, portable and large field-of-view gamma camera to identify, locate and quantify gamma-ray emitting radioisotopes in real-time has been developed. The device delivers spectroscopic and imaging capabilities, which allow one to use…
We calculate the total gamma-ray line emission at ~450 keV that accompanies 7-Li and 7-Be production by cosmic-ray interactions, including the delayed line emission at 0.478 MeV from 7-Be radioactive decay. We present a new gamma-ray…
We consider a mechanism which allows to decrease attenuation of high energy gamma ray flux from gamma ray burst GRB 221009A. The mechanism is based on the existence of a heavy $m_N\sim0.1\,\mathrm{MeV}$ mostly sterile neutrino $N$ which…
A standard high purity germanium (HPGe) detector was used to determine the previously unknown neutron activity of a weak americium-beryllium (AmBe) neutron source. Gamma rays were created through 27Al(n,n'), 27Al(n,gamma) and 1H(n,gamma)…
Within a multicomponent dark matter scenario, novel gamma-ray signals may arise from the decay of the heavier dark matter component into the lighter. For a scalar dark sector of this kind, the decay $\phi_2\rightarrow\phi_1 \gamma$ is…
We have measured proton and alpha-particle branching ratios of excited states in 19Ne formed using the 19F(3He,t) reaction at a beam energy of 25 MeV. These ratios have a large impact on the astrophysical reaction rates of 15O(alpha,gamma),…
Aims. The accretion of stars onto the central supermassive black hole at the center of the Milky Way is predicted to generate large fluxes of subrelativistic ions in the Galactic center region. We analyze the intensity, shape and spatial…
The radioactive decay of the freshly synthesized $r$-process nuclei ejected in compact binary mergers power optical/infrared macronovae (kilonovae) that follow these events. The light curves depend critically on the energy partition among…
Indications for a gamma-ray line(s) signal towards the Galactic center at an energy of about 130 GeV have been recently presented. While dark matter annihilations are a viable candidate for this signal, it is generally expected that such a…
The origin of the cosmic gamma-ray background at 1-20 MeV remains a mystery. We show that gamma-ray emission accompanying annihilation of 20 MeV dark matter particles explains most of the observed signal. Our model satisfies all of the…
Astrophysical gamma-ray spectroscopy is an invaluable tool for studying nuclear astrophysics, supernova structure, recent star formation in the Milky Way and mixing of nucleosynthesis products in the interstellar medium. After a short,…
The present design of the new space observatory GAMMA-400 is presented in this paper. The instrument has been designed for the optimal detection of gamma rays in a broad energy range (from ~100 MeV up to 3 TeV), with excellent angular and…
Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ~ 10 GeV - 1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which…