Comparison of the Nuclear-Reaction Energy Scale with the Gamma-Ray Energy Scale

1971 ◽  
Vol 4 (3) ◽  
pp. 930-933 ◽  
Author(s):  
H. Stocker ◽  
A. A. Rollefson ◽  
A. F. Hrejsa ◽  
C. P. Browne
Keyword(s):  
Nuclear Reaction ◽  
Gamma Ray ◽  
Energy Scale ◽  
Reaction Energy

Gamma-ray production in the 170Er(p,n)170Tm nuclear reaction

Open Physics ◽  
2010 ◽  
Vol 8 (4) ◽  
Author(s):  
Alexandru Mihailescu ◽  
Gheorghe Cata-Danil
Keyword(s):  
High Resolution ◽  
Energy Range ◽  
Nuclear Reaction ◽  
Gamma Rays ◽  
Compound Nucleus ◽  
Beam Energy ◽  
Gamma Ray ◽  
Excitation Functions ◽  
Γ Ray ◽  
First Time

AbstractFor the first time discrete gamma-rays following the nuclear reaction 170Er(p,n)170Tm with enriched target were measured with a high resolution GeHP spectrometer. Protons delivered by the Bucharest FN Tandem Van de Graaff accelerator bombarded a thin self-supporting film of enriched erbium. Measured γ-ray energies (Eγ), their relative intensities (Iγ) and corresponding excitation functions for the beam energy range 2.0–3.6 MeV are reported in the present work. The measured excitation functions were fairly well reproduced by compound nucleus calculations based on the Hauser-Feshbach formalism.

scholarly journals Interpreting correlated observations of cosmic rays and gamma-rays from Centaurus A with a proton blazar inspired model

2020 ◽  
Vol 500 (1) ◽  
pp. 1087-1094
Author(s):  
Prabir Banik ◽  
Arunava Bhadra ◽  
Abhijit Bhattacharyya
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Energy Scale ◽  
Electromagnetic Spectrum ◽  
Ultrahigh Energy ◽  
Large Area ◽  
Centaurus A

ABSTRACT The nearest active radio galaxy Centaurus (Cen) A is a gamma-ray emitter in GeV–TeV energy scale. The high energy stereoscopic system (HESS) and non-simultaneous Fermi–Large Area Telescope observation indicate an unusual spectral hardening above few GeV energies in the gamma-ray spectrum of Cen A. Very recently the HESS observatory resolved the kilo parsec (kpc)-scale jets in Centaurus A at TeV energies. On the other hand, the Pierre Auger Observatory (PAO) detects a few ultrahigh energy cosmic ray (UHECR) events from Cen-A. The proton blazar inspired model, which considers acceleration of both electrons and hadronic cosmic rays in active galactic nuclei (AGN) jet, can explain the observed coincident high-energy neutrinos and gamma-rays from Ice-cube detected AGN jets. Here, we have employed the proton blazar inspired model to explain the observed GeV–TeV gamma-ray spectrum features including the spectrum hardening at GeV energies along with the PAO observation on cosmic rays from Cen-A. Our findings suggest that the model can explain consistently the observed electromagnetic spectrum in combination with the appropriate number of UHECRs from Cen A.

Extragalactic background light inhomogeneities and Lorentz-Invariance Violation in gamma-gamma absorption and Compton scattering

2019 ◽  
Vol 15 (S356) ◽  
pp. 364-364
Author(s):  
Hassan Abdalla
Keyword(s):  
Compton Scattering ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Energy Scale ◽  
Fundamental Physics ◽  
Extragalactic Background Light ◽  
Invariance Violation ◽  
Gamma Absorption ◽  
The Impact ◽  
Planck Energy

AbstractAt energies approaching the Planck energy scale 1019GeV, several quantum-gravity theories predict that familiar concepts such as Lorentz (LIV) symmetry can be broken. Such extreme energies are currently unreachable by experiments on Earth, but for photons traveling over cosmological distances the accumulated deviations from the Lorentz symmetry may be measurable using the Cherenkov Telescope Array (CTA). To study the spectral hardening feature observed in some VHE gamma-ray blazars, we calculate the reduction of the EBL gamma-gamma opacity due to the existence of underdense regions along the line of sight to VHE -gamma ray sources and we compared with the possibility of a LIV signature. Considering the LIV effect, we found that the cosmic opacity for VHE-gamma rays with energy more than 10 TeV can be strongly reduced. I will further discuss the impact of LIV on the Compton scattering process, and how future CTA observations may open an exciting window on studies of the fundamental physics.

Anticoincidence Shielded Gamma‐Ray Spectrometer for Nuclear Reaction Studies

1966 ◽  
Vol 37 (8) ◽  
pp. 991-999 ◽  
Author(s):  
Albert E. Evans ◽  
Bernard Brown ◽  
Jerry B. Marion
Keyword(s):  
Nuclear Reaction ◽  
Gamma Ray ◽  
Gamma Ray Spectrometer

scholarly journals Constraints on Lorentz Invariance Violation From Optical Polarimetry of Astrophysical Objects

2018 ◽  
Author(s):  
Fabian Kislat
Keyword(s):  
Standard Model ◽  
Quantum Gravity ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Effective Field ◽  
Energy Scale ◽  
Theory Of Relativity ◽  
Standard Model Extension ◽  
Polarization Measurements ◽  
The Standard Model

Theories of quantum gravity suggest that Lorentz invariance, the fundamental symmetry of the Theory of Relativity, may be broken at the Planck energy scale. While any deviation from conventional Physics must be minuscule in particular at attainable energies, this hypothesis motivates ever more sensitive tests of Lorentz symmetry. In the photon sector, astrophysical observations, in particular polarization measurements, are a very powerful tool because tiny deviations from Lorentz invariance will accumulate as photons propagate over cosmological distances. The Standard-Model Extension (SME) provides a theoretical framework in the form of an effective field theory that describes low-energy effects due to a more fundamental quantum gravity theory by adding additional terms to the Standard Model Lagrangian. These terms can be ordered by the mass dimension d of the corresponding operator and lead to a wavelength, polarization, and direction dependent phase velocity of light. In this paper, we analyze optical polarization measurements from 63 Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRBs) in order to search for Lorentz violating signals. We derive the first set limits on each of the 10 individual birefringent coefficients of the minimal SME with d = 4, with 95% confidence limits on the order of 10−34 on the dimensionless coefficients.

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