scholarly journals The Photoneutron Cross Section of Natural Osmium

1977 ◽  
Vol 30 (6) ◽  
pp. 677 ◽  
Author(s):  
Su Su ◽  
RH Sambell ◽  
EG Muirhead ◽  
BM Spicer
Keyword(s):  
Cross Section ◽  
Giant Dipole Resonance ◽  
Yield Data ◽  
Yield Curves ◽  
Dipole Resonance ◽  
Theoretical Predictions ◽  
Show Evidence ◽  
Bremsstrahlung Yield ◽  
The Absolute ◽  
The Cross

The absolute (y, xn) cross section of natural osmium is extracted from bremsstrahlung yield curves measured from the lowest (y, n) threshold of osmium isotopes up to 28 MeV in energy steps of 0�2 MeV. The VBPL method of Bramanis et al. (1972) has been used to unfold the cross section from bremsstrahlung yield data. The results do not show evidence of significant amounts of splitting of the giant dipole resonance, as might be expected from the theoretical predictions of Sedlmayr et al. (1974), but at the same time are not inconsistent with their general features.

ISOSPIN DECOMPOSITION OF pp → NNππ CROSS SECTIONS — DO WE SEE A SIGN OF Δ(1600) EXCITATION IN THE nnπ+π+ CHANNEL?

2009 ◽  
Vol 24 (02n03) ◽  
pp. 450-453
Author(s):  
◽  
T. SKORODKO ◽  
M. BASHKANOV ◽  
D. BOGOSLOWSKY ◽  
H. CALÉN ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Pion Production ◽  
Significant Contribution ◽  
Differential Cross Sections ◽  
Pp Collisions ◽  
Theoretical Predictions ◽  
Order Of Magnitude ◽  
The Cross

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.

Resolution of Bremsstrahlung Experiments

1961 ◽  
Vol 14 (1) ◽  
pp. 174 ◽  
Author(s):  
HH Thies
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Curve Fitting ◽  
Optical Resolution ◽  
Yield Data ◽  
Statistical Errors ◽  
Practical Evaluation ◽  
Bremsstrahlung Yield

This paper investigates how mathematical approximations and statistical errors are transmitted into computed cross sections in the analysis of experimental bremsstrahlung yield data. The resolution of bremsstrahlung experiments is defined in analogy with optical resolution and an expression for the practical evaluation of resolution is derived. Methods of cross-section computation, and smoothing and curve-fitting are discussed.

The 11B(d,γ0)13C reaction in the region of the giant dipole resonance

1981 ◽  
Vol 59 (6) ◽  
pp. 781-783 ◽  
Author(s):  
G. Kajrys ◽  
W. Del Bianco ◽  
J. Kim ◽  
S. Landsberger ◽  
R. Lecomte ◽  
...  
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Giant Dipole Resonance ◽  
Yield Curve ◽  
Plastic Scintillator ◽  
Resonant Structure ◽  
Crystal Spectrometer ◽  
Dipole Resonance ◽  
Γ Rays

The 90° differential cross section of the 11B(d,γ0)13C reaction has been measured at deuteron energies from 1.95 to 12.0 MeV in steps varying from 100 to 200 keV. The γ-rays have been detected by a 23 cm long × 23 cm diameter NaI(Tl) crystal spectrometer enclosed in a plastic scintillator anticoincidence shield. The yield curve shows a resonant structure at the energies Eexe = 20.4 ± 0.1 and 22.0 ± 0.2 MeV.

A measurement of the cross section for production of He + (2 S ) ions by electron impact excitation of ground state helium ions

1966 ◽  
Vol 290 (1420) ◽  
pp. 74-93 ◽  
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Cross Sections ◽  
Absolute Magnitude ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Close Coupling ◽  
Born Cross Section ◽  
The Absolute ◽  
The Cross

A crossed beams method has been used to measure the cross section for the production of He + (2 S ) by electrons incident upon He + (1 S ) in the energy range from threshold to 750 eV. The cross section was measured in arbitrary units with an accuracy of ± 5 % and at the higher energies its energy dependence is in close agreement with that calculated by means of the plane-wave Born approximation. Consequently the cross section has been normalized to the plane-wave Born cross section at energies between 435 and 750 eV to obtain the absolute magnitude. An independent estimate of the absolute magnitude was made to with in ± 30 % using only the experimental parameters, and the absolute cross sections given by the two methods agree within the experimental uncertainties. The normalized cross section is compared with cross sections given by the close-coupling approximation and various Coulomb-Born approximations. At the lower energies the normalized cross section is considerably smaller than any of the theoretical values, but the measurements are consistent with the existence of a finite cross section at threshold if the energy spread of the electron beam is taken in to account.

The (g, p) and (g, n) Reactions in Molybdenum

1968 ◽  
Vol 21 (5) ◽  
pp. 765 ◽  
Author(s):  
RW Gellie
Keyword(s):  
Activation Analysis ◽  
Cross Sections ◽  
Giant Dipole Resonance ◽  
Dipole Resonance ◽  
Isospin Splitting ◽  
The Cross ◽  
Medium Weight ◽  
Residual Activation

Measurements have been made of the cross sections for some of the (g,p) and (y, n) reactions in molybdenum using the technique of residual activation analysis. The gross structure of these cross sections is compared with previous measurements and the results are interpreted as evidence for the isospin splitting of the giant dipole resonance in medium weight nuclei.

scholarly journals Constraining the in-medium nucleon-nucleon cross section from the width of nuclear giant dipole resonance

2020 ◽  
Vol 807 ◽  
pp. 135532 ◽  
Author(s):  
Rui Wang ◽  
Zhen Zhang ◽  
Lie-Wen Chen ◽  
Che Ming Ko ◽  
Yu-Gang Ma
Keyword(s):  
Cross Section ◽  
Giant Dipole Resonance ◽  
Nucleon Nucleon ◽  
Dipole Resonance

New Results on Double Charmonium Production in e+e- Annihilation at $\sqrt{s} \approx 10.6~{\rm GeV}$ with the Belle Detector

2005 ◽  
Vol 20 (16) ◽  
pp. 3617-3620
Author(s):  
◽  
T. Ziegler
Keyword(s):  
Cross Section ◽  
Strong Evidence ◽  
Previous Analysis ◽  
Charmonium State ◽  
Data Set ◽  
Charmonium Production ◽  
Belle Detector ◽  
Theoretical Predictions ◽  
Order Of Magnitude ◽  
The Cross

Extending a previous analysis1 the double charmonium production [Formula: see text] and [Formula: see text] has been investigated with a data set of 155 fb-1 with the Belle detector. Theoretical predictions for the cross section are one order of magnitude lower than the measured value and this discrepancy is still not understood. In a very recent update with a dataset of 285 fb-1 strong evidence for a new charmonium state at a mass of 3.940 GeV was found.

Giant dipole resonance in 4He

1980 ◽  
Vol 58 (11) ◽  
pp. 1555-1559 ◽  
Author(s):  
J. J. Bevelacqua
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Giant Dipole Resonance ◽  
Reasonable Agreement ◽  
Center Of Mass ◽  
Nucleon Nucleon ◽  
Nucleon Interaction ◽  
R Matrix ◽  
Dipole Resonance ◽  
Nucleon Nucleon Interaction

The 4He giant dipole resonance is calculated with the generalized R-matrix method of Lane and Robson. The model treats the center of mass correctly and includes noncentral components in the nucleon–nucleon interaction via the Sussex interaction. The 4He(γ,p)3H and 4He(γ,n)3He cross sections are sensitive to the 4He level spectrum, but are in reasonable agreement with the photonuclear data for level schemes which agree with the spectrum suggested by Fiarman and Meyerhof (FM). Other spectra which bracket the FM levels lead to poorer photonuclear cross sections. R-matrix model results also lead to a (γ,p)/(γ,n) cross section ratio which is about unity.

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