The Scattering of Positrons by Helium: Total Cross Sections up to 270 eV

1975 ◽  
Vol 53 (10) ◽  
pp. 962-967 ◽  
Author(s):  
B. Jaduszliwer ◽  
A. Nakashima ◽  
D. A. L. Paul
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Reasonable Agreement ◽  
Experimental Results ◽  
Formation Cross Section ◽  
Sum Rule ◽  
Total Cross Sections ◽  
High Energies

The total cross sections for the scattering of positrons by helium have been measured by the method of transmission in the 16 to 270 eV energy range. The experimental results are higher than those of Canter et al. but are in reasonable agreement with recent results of Griffith et al., and at high energies tend towards Born approximation calculations. The integral of the cross section over positron momentum is smaller than the sum rule estimate made by Bransden et al. A tentative value of (0.034 ± 0.017)πa02 is assigned to the positronium formation cross section at threshold.

DOUBLE PION PHOTOPRODUCTION EXPERIMENT AT LNS–TOHOKU

2008 ◽  
Vol 23 (27n30) ◽  
pp. 2313-2316 ◽  
Author(s):  
◽  
H. KANDA ◽  
N. CHIGA ◽  
Y. FUJII ◽  
K. FUTATSUKAWA ◽  
...  
Keyword(s):  
Total Cross Section ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Pion Photoproduction ◽  
Total Cross Sections ◽  
Free Proton ◽  
Double Pion ◽  
The Cross

The total cross sections for the π+π− photoproduction on the deuteron were measured in an energy range of 0.8 to 1.1 GeV. The obtained total cross section for the quasi-free π+π− photoproduction on the deuteron was about 60 % of those on the free proton. The cross section for Δ++Δ− photoproduction was derived from the non-quasi-free π+π− photoproduction events. It was smaller than the previous data.

scholarly journals Dipole Pomeron and Proton-Proton Elastic Scattering at High Energies

1980 ◽  
Vol 33 (3) ◽  
pp. 481 ◽  
Author(s):  
Mohammad Saleem ◽  
Fazal-e Aleem ◽  
Mujahid Kamran
Keyword(s):  
Elastic Scattering ◽  
Energy Range ◽  
Cross Sections ◽  
High Energy ◽  
Proton Proton ◽  
Total Cross Sections ◽  
High Energies ◽  
Proton Elastic Scattering

The differential and total cross sections for high energy pp elastic scattering in the energy range 30�8:;;; st :;;; 62 GeV, with -t extending up to 8 (GeV/c)2, have been fitted with a dipole pomeron model.

EXPERIMENTAL STUDY OF SINGLE-ELECTRON-CAPTURE CROSS SECTIONS BY LOW-ENERGY $N^+_2$ AND N+ IONS IN N2 MOLECULAR GAS

2002 ◽  
Vol 11 (06) ◽  
pp. 567-572 ◽  
Author(s):  
A. T. HASAN ◽  
T. J. GRAY
Keyword(s):  
Electron Capture ◽  
Cross Section ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Experimental Results ◽  
Single Electron ◽  
Molecular Gas ◽  
Total Cross Sections ◽  
Single Electron Capture ◽  
Capture Cross Sections

Absolute total cross sections for single-electron-capture are measured for [Formula: see text] and N+ ions traversing N2 molecular gas of collision energies in the range of 0.60 to 1.5 keV. These cross sections are found to be in the range of 3.97 - 6.25 Å2 for [Formula: see text] ions, and in the range of 0.46 - 1.67 Å2 for N+ ions. A comparison is made between the present measurements of the total cross sections of the N+ + N2 system and all the experimental results, which are represented by B. G. Lindsay et al.,1 for the O+ + N2 system. The present measurements of the total cross section of the N+ + N2 system are in partial agreement with measurements of B. G. Lindsay et al.,1 and in an excellent agreement with the measurements of Moran et al.,2 The present measurements of the total cross sections of the [Formula: see text] system are compared to the theoretical calculations and the experimental results of the same system.23 The results are in disagreement with each other.

Pion-nucleon scattering at high energies

1966 ◽  
Vol 289 (1419) ◽  
pp. 500-508 ◽  
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Charge Exchange ◽  
Cross Sections ◽  
Scattering Amplitude ◽  
Forward Scattering Amplitude ◽  
Nucleon Scattering ◽  
Total Cross Sections ◽  
High Energies ◽  
Pion Nucleon

The charge exchange forward scattering amplitude 1.1 1.2 using an interpolation of the total cross sections which includes the results presented by Dr Galbraith at this meeting. From F (-) follows a prediction for the charge exchange forward cross section (c.m. system) 1.3 which will be compared with the experimental data including those presented by Dr Falk-Vairant and Dr Guerriero.

Measurement of total cross sections (e+, Ne) and (e+, Ar)

1976 ◽  
Vol 54 (17) ◽  
pp. 1741-1748 ◽  
Author(s):  
J-S. Tsai ◽  
L. Lebow ◽  
D. A. L. Paul
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Scattering Amplitude ◽  
Scattering Length ◽  
Forward Scattering Amplitude ◽  
Sum Rule ◽  
Total Cross Sections ◽  
Scattering Lengths ◽  
Momentum Integral

The total cross sections for positrons on neon and argon atoms have been measured in the energy ranges 15 eV to 272.5 eV and 25 eV to 300 eV respectively. The cross sections indicate clearly that Born values will not be reached until at least 3 KeV. Interpolating between the measured and the valid Born regions has allowed an application of the sum rule which connects scattering length. Born forward scattering amplitude, and the momentum-integral over the total cross section. This procedure gives scattering lengths as = −0.53 ± 0.15 Bohr radii for neon and as = −2.8 ± 0.7 Bohr radii for argon; the errors include maximum credible uncertainties in the interpolations.

Measurement of Li X-ray fluorescence production cross sections and intensity ratios of some elements at 59.54 keV

2015 ◽  
Vol 93 (10) ◽  
pp. 1057-1066 ◽  
Author(s):  
F. Akman ◽  
R. Durak ◽  
M.R. Kaçal ◽  
M.F. Turhan
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Reasonable Agreement ◽  
Production Cross ◽  
Radioactive Source ◽  
Experimental Results ◽  
X Ray ◽  
Intensity Ratios ◽  
Theoretical Results ◽  
Excitation Geometry

The Li (i = l, α, β, γ) X-ray production cross section and Lα/Ll, Lα/Lβ, Lα/Lγ, Ll/Lβ, Ll/Lγ, and Lβ/Lγ intensity ratio values for Yb, Ta, W, Hg, Tl, Pb, Bi, Th, and U have been determined using an excitation geometry at 59.54 keV incident photon energy. The measurements were performed using an Am-241 annular radioactive source and a high resolution Si(Li) detector. The experimental results of Li X-ray production cross sections and intensity ratios were compared with three different theoretical results and other available experimental results in the literature. Reasonable agreement is typically observed between the present and theoretical results.

Comparison of D–T and D– 3 He at low energies

1953 ◽  
Vol 218 (1134) ◽  
pp. 432-438 ◽  
Keyword(s):  
Angular Distribution ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Coulomb Barrier ◽  
Simple Theory ◽  
Absolute Cross Section ◽  
Total Cross Sections ◽  
Gas Target ◽  
Low Energies

A thin gas target was used to measure the absolute cross-section and angular distribution of α -particles from the two ‘ mirror ’ reactions D– 3 H and D– 3 He for deuteron energies below 45 keV. The reactions were found to be isotropic and the variations of the total cross-sections over the energy range 20 to 45 keV can be expressed by the simple Gamow theory of penetration of the coulomb barrier. The simple theory assuming the same energy-independent nuclear parameters for the mirror nuclei 3 H and 3 He was unable to account for the observed cross-sections of these two reactions.

scholarly journals Odderon and pomeron as fractal dimension in pp and p̄p total cross-sections

2016 ◽  
Vol 31 (10) ◽  
pp. 1650066 ◽  
Author(s):  
F. S. Borcsik ◽  
S. D. Campos
Keyword(s):  
Fractal Dimension ◽  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Fractal Dimensions ◽  
Total Cross Sections ◽  
High Energies ◽  
Fitting Procedure ◽  
Low Energies ◽  
Section Structure

In this paper, one presents a naive parametrization to [Formula: see text] and [Formula: see text] total cross-sections. The main goal of this parametrization is to study the possible fractal structure present in the total cross-section. The result of the fitting procedure shows two different fractal dimensions: a negative (low-energies) and a positive (high-energies). The negative fractal dimension represents the emptiness of the total cross-section structure and the positive represents the filling up process with the energy increase. Hence, the total cross-section presents a multifractal behavior. At low-energies, the odderon exchange may be associated with the negative fractal dimension and at high-energies, the pomeron may be associated with the positive fractal dimension. Therefore, the exchange of odderons and pomerons may be viewed as a transition from a less well-defined to a more well-defined internal structure, depending on the energy.

scholarly journals γγ TOTAL CROSS-SECTION AT HIGH ENERGIES

2000 ◽  
Vol 15 (01) ◽  
pp. 9-13 ◽  
Author(s):  
C. BOURRELY ◽  
J. SOFFER ◽  
TAI TSUN WU
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Total Cross Sections ◽  
Energy Scattering ◽  
High Energies ◽  
High Energy Scattering ◽  
The Impact

We show that the rising total cross-sections σ(γγ→ hadrons) recently observed by the L3 and OPAL collaborations at LEP are fully consistent with the impact-picture for high-energy scattering. The impact picture is then used to predict this γγ total cross-section at higher energies, and confirm the universal increase of total cross-sections including those of pp, [Formula: see text] and γp.

The K -shell ionization of atoms by high-energy electrons

1958 ◽  
Vol 247 (1251) ◽  
pp. 550-556 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Marked Improvement ◽  
Relativistic Effects ◽  
High Energy ◽  
High Energies ◽  
High Energy Electrons ◽  
Shell Ionization ◽  
Good Agreement

An expression for the cross-section for K -shell ionization of atoms by electrons is obtained by using Moller’s relativistic modification of the Born approximation. Results are presented for the elements with atomic numbers less than 30. For nickel the calculated cross-sections are in good agreement with those measured by Kirkpatrick and his collaborators, a marked improvement due to the allowance for relativistic effects being found at high energies of impact. The normalization of the wave function of the ejected electron is discussed in the appendix.

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