D(3He, γ)5Li reaction from 2 to 11 MeV

1968 ◽  
Vol 46 (14) ◽  
pp. 1585-1587 ◽  
Author(s):  
W. Del Bianco ◽  
F. Lemire ◽  
R. J. A. Lévesque ◽  
J. M. Poutissou
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Gamma Ray ◽  
Upper Limits ◽  
Integrated Cross Section

The 90° yield of the D(3He, γ)5Li reaction has been measured from 2.3 to 11.2 MeV 3He energy. No clear evidence of a level in 5Li has been found over this energy range. The upper limits for the resonance integrated cross section and gamma-ray width were estimated to be σint ~ 15 μb MeV and Γγ ~ 100eV, respectively.

scholarly journals The Photoneutron Cross Section of 9Be in the Intermediate Energy Range

1959 ◽  
Vol 12 (1) ◽  
pp. 21 ◽  
Author(s):  
HH Thies ◽  
BM Spicer ◽  
JEE Baglln
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Level Scheme ◽  
Complex Shape ◽  
Intermediate Energy ◽  
Bremsstrahlung Radiation ◽  
Integrated Cross Section ◽  
The Cross

The photoneutron cross section of DBe has been measured in the region from 6�5 to 18 MeV, using filtered bremsstrahlung radiation from an 18 MeV synchrotron. The integrated cross section is in agreement with an earlier experiment, but increased resolution has shown a more complex shape, with sharp maxima at 1l�25�O�2 and 13� 25 � 0�2 MeV. The significant features of the cross section are discussed and compared with the level scheme as it is known at present.

scholarly journals Very High Energy Gamma-ray Observations of AGN with CANGAROO

2002 ◽  
Vol 19 (1) ◽  
pp. 26-28 ◽  
Author(s):  
Kyoshi Nishijima
Keyword(s):  
Energy Range ◽  
Energy Region ◽  
Gamma Ray ◽  
High Energy ◽  
Large Zenith Angle ◽  
Upper Limits ◽  
Very High Energy ◽  
Energy Gamma ◽  
Bl Lacs ◽  
Very High

AbstractWe have observed eight AGN since 1993 in the energy region above several hundred GeV using the CANGAROO telescopes. We observed Mrk 421 for ten nights with the CANGAROO-II 10 m telescope during its active state in early 2001 using the very large zenith angle technique. Our preliminary result implies the detection of gamma-ray emission from Mrk 421 in the energy range above 9.3 TeV. The high energy peaked BL Lacs (HBLs) PKS 2005–489 and PKS 2155–304 have been also observed. No statistically significant signals are found for both HBLs and flux upper limits are obtained. A summary of results of observations of AGN is presented in this paper.

MEASUREMENT OF NUCLEAR GAMMA-RAY ABSORPTION IN CARBON

1953 ◽  
Vol 31 (4) ◽  
pp. 636-656 ◽  
Author(s):  
R. N. H. Haslam ◽  
R. J. Horsley ◽  
H. E. Johns ◽  
L. B. Robinson
Keyword(s):  
Cross Section ◽  
Gamma Ray ◽  
Nuclear Scattering ◽  
Absorption Mechanism ◽  
Nuclear Absorption ◽  
Resonance Behavior ◽  
Continuous Absorption ◽  
Γ Rays ◽  
Integrated Cross Section ◽  
Nuclear Detectors

The cross section for the absorption of γ rays by carbon has been determined as a function of photon energy by means of "nuclear detectors". The electronic absorption coefficients in the energy range 12 to 20 Mev. are found to be about 1% lower than the theoretical values. The nuclear absorption is shown to exhibit a resonance behavior. The integrated cross section in carbon is considerably lower than predicted. The contribution of nuclear scattering is found to be negligible. Differences in results as determined by three different detecting reactions, C12(γ, n)C11, O16(γ, d)P15, and S32(γ, d)P30, are discussed on the basis of detector sensitivity. It is suggested that the absorption mechanism can be represented by a continuous absorption on which is superimposed absorption peaks.

CONSTRAINING DARK MATTER ANNIHILATION WITH NEUTRINOS AND GAMMA RAYS

2011 ◽  
Vol 01 ◽  
pp. 245-251
Author(s):  
NICOLE F. BELL
Keyword(s):  
Dark Matter ◽  
Total Cross Section ◽  
Cross Section ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Mass Range ◽  
Dark Matter Halo ◽  
Dark Matter Annihilation ◽  
Upper Limits ◽  
Wide Range

We examine dark matter annihilation in galaxy halos. By considering annihilation into all Standard Model particles we show that the least detectable final states, namely neutrinos, define a strong general upper bound on the total cross section. This limit is much stronger than the unitarity bound in the most interesting mass range and implies annihilation cannot significantly modify dark matter halo density profiles. We also calculate conservative upper limits on the self-annihilation cross section to monoenergetic gamma rays over a wide range of dark matter masses, using gamma-ray data from the Milky Way, Andromeda (M31), and the cosmic background. We compare gamma-ray-based and neutrino-based upper limits on the total cross section.

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Gamma Ray ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Solar Neutron ◽  
Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

scholarly journals Spin-one dark matter and gamma ray signals from the galactic center

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
H. Hernández-Arellano ◽  
M. Napsuciale ◽  
S. Rodríguez
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Gamma Ray ◽  
Galactic Center ◽  
Photon Emission ◽  
Scalar Coupling ◽  
Initial State ◽  
Internal Bremsstrahlung ◽  
Resonance Effects ◽  
State Radiation

Abstract In this work we study the possibility that the gamma ray excess (GRE) at the Milky Way galactic center come from the annihilation of dark matter with a (1, 0) ⊕ (0, 1) space-time structure (spin-one dark matter, SODM). We calculate the production of prompt photons from initial state radiation, internal bremsstrahlung, final state radiation including the emission from the decay products of the μ, τ or hadronization of quarks. Next we study the delayed photon emission from the inverse Compton scattering (ICS) of electrons (produced directly or in the prompt decay of μ, τ leptons or in the hadronization of quarks produced in the annihilation of SODM) with the cosmic microwave background or starlight. All these mechanisms yield significant contributions only for Higgs resonant exchange, i.e. for M ≈ MH /2, and the results depend on the Higgs scalar coupling to SODM, gs. The dominant mechanism at the GRE bump is the prompt photon production in the hadronization of b quarks produced in $$ \overline{D}D\to \overline{b}b $$ D ¯ D → b ¯ b , whereas the delayed photon emission from the ICS of electrons coming from the hadronization of b quarks produced in the same reaction dominates at low energies (ω < 0.3 GeV ) and prompt photons from c and τ , as well as from internal bremsstrahlung, yield competitive contributions at the end point of the spectrum (ω ≥ 30 GeV ). Taking into account all these contributions, our results for photons produced in the annihilation of SODM are in good agreement with the GRE data for gs ∈ [0.98, 1.01] × 10−3 and M ∈ [62.470, 62.505] GeV . We study the consistency of the corresponding results for the dark matter relic density, the spin-independent dark matter-nucleon cross-section σp and the cross section for the annihilation of dark matter into $$ \overline{b}b $$ b ¯ b , τ+τ−, μ+μ− and γγ, taking into account the Higgs resonance effects, finding consistent results in all cases.

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