Pion-nucleon resonances and their effect upon π ± p total cross sections

1966 ◽  
Vol 289 (1419) ◽  
pp. 521-530 ◽  
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Recent Experiment ◽  
Isotopic Spin ◽  
Spin States ◽  
Total Cross Sections ◽  
Nucleon Resonances ◽  
Pion Nucleon

Precise measurements of the total cross sections of positive and negative π mesons on hydrogen have revealed the presence of structure or enhancements in these cross sections at various momenta up to 3 GeV/ c . The present paper discusses measurements of this type and in particular, a recent experiment to search for structure in the region 3 to 7 GeV/ c , where previous experiments have shown that, if structure were present, it was likely to reveal itself as an amplitude in the total cross section of 1 mb or less. The recent measurements indicate four regions of structure, two in each of the isotopic spin states 3/2 and 1/2. The possible relation of these regions of structure to the formation of pion-nucleon resonances is discussed.

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.

THE SPIN CONTRIBUTION TO THE pp-TOTAL CROSS-SECTION AT HIGH ENERGY

1998 ◽  
Vol 13 (09) ◽  
pp. 1515-1522 ◽  
Author(s):  
E. A. ANDREEVA ◽  
M. N. STRIKHANOV ◽  
S. B. NURUSHEV
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Spin Projection ◽  
Total Cross Sections ◽  
Spin Effects ◽  
Dependent Term ◽  
Spin Interactions ◽  
200 Gev

The experimental data on the pp-total cross-sections including the spin-dependent parts are analyzed with the goal to determine the contribution of spin interactions at high energies. Based on the Regge model with cuts, the energy dependencies of such contributions are estimated for two spin-dependent terms: (1) the total spin dependent term, σ1 and (2) the spin projection dependent term, σ2. The estimates show that their contributions to the unpolarized total cross section, σ0, decrease with energy from several % around 2 GeV/c to 10-2% around 200 GeV/c. The assumption σ1= -σ2 does not seem to be correct, while the hypothesis 3 σ1=-σ2 is more preferable, especially in the measured energy interval 2-6 GeV. There is a clear indication that the spin effects are sensitive to the pomeron intercept at - t=0 (GeV/c)2. In order to pin down such effects the spin dependent total cross-sections must be measured with precisions better than 10 μb at 200 GeV/c.

η PHOTO-PRODUCTION ON THE DEUTERON AT LNS, TOHOKU UNIVERSITY

2010 ◽  
Vol 19 (12) ◽  
pp. 2393-2399 ◽  
Author(s):  
T. Ishikawa
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Systematic Uncertainty ◽  
Cross Sections ◽  
Energy Region ◽  
Solid Angle ◽  
Total Cross Sections ◽  
Nuclear Science ◽  
Electro Magnetic ◽  
Photo Production

The differential and total cross sections were measured for the γp → ηp and γd → ηpn reactions at Eγ ≤ 1150 MeV by using an electro-magnetic (EM) calorimeter SCISSORS II at the Laboratory of Nuclear Science (LNS), Tohoku University. The total cross section on the deuteron shows a bump around Eγ = 1 GeV , while no bump is observed in the same energy region of that on the proton. This bump is attributed to be a nucleon resonance excited from the neutron, and it is a candidate of anti-decuplet penta-quark baryons with hidden strangeness. It was difficult, however, to detect all the γ's coming from η decay since the solid angle of SCISSORS II was only 12.6% in total. Statistics of the detected η produced events is poor and systematic uncertainty of the obtained cross section is not small due to low acceptance. A new EM calorimeter complex called FOREST with a solid angle of about 4π sr has been constructed. The spin and parity of the relevant resonance are expected to be determined by the experiments with FOREST.

scholarly journals Effect of Rapidly Rising Proton?Proton Total Cross Sections on Idealized Extensive Air Showers

1972 ◽  
Vol 25 (6) ◽  
pp. 679
Author(s):  
JA Campbell
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Strong Interaction ◽  
Extensive Air Showers ◽  
Proton Scattering ◽  
Air Showers ◽  
Proton Proton ◽  
Total Cross Sections ◽  
First Time

A simulation of extensive air showers above 1013 eV in which proton?proton scattering takes place partly through a medium-strong interaction is reported. In previous papers the simulation has been shown to be in fair agreement with observational data. The present version includes for the first time the assumption that the total cross section for proton-proton scattering increases with energy, as concluded in a recent paper by Yodh, Pal, and Trefil. The effect of the assumption is to make a noticeably better agreement between the simulation and the data.

INCLUSIVE REACTIONS AND TOTAL CROSS SECTIONS WITH POLARIZED INITIAL STATES

1986 ◽  
Vol 01 (01) ◽  
pp. 211-225 ◽  
Author(s):  
GARY R. GOLDSTEIN ◽  
MICHAEL J. MORAVCSIK
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Final State ◽  
Total Cross Sections ◽  
Initial States

Total cross section measurements and the type of inclusive reactions in which no final-state polarizations are measured are discussed. The numbers and kinds of independent non-zero experiments are given and related to the exclusive reaction amplitudes. Only a well-specified and limited type of bilinear product of exclusive reaction amplitudes enter the picture. Certain classes of theories imply certain simple relationships among the observables. The main results of the investigation are summarized in Sec. 5.

ELASTIC AND INELASTIC SCATTERING OF POSITRONS BY POTASSIUM ATOMS

2007 ◽  
Vol 21 (10) ◽  
pp. 625-637 ◽  
Author(s):  
SALAH YASEEN EL-BAKRY
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Positronium Formation ◽  
Electron Model ◽  
Static Approximation ◽  
Total Cross Sections ◽  
Energy Formula ◽  
The One ◽  
Good Agreement

The investigations of the elastic and inelastic collisions of positrons with potassium atoms, K (1s2, 2s2, 2p6, 3s2, 3p6, 4s), are presented. The potassium target atoms are described using Clementi–Roetti wavefunctions within the framework of the one-valence-electron model. The total cross-sections which correspond to eight partial cross-sections are calculated at 34 values of the incident energy [Formula: see text] using the coupled-static approximation. The resulting total elastic, ground- and excited-positronium formation cross-sections are compared with experimental results and those calculated by other authors. In the vicinity of 6 eV, and consistent with the measurements of Parikh et al.,2 our total cross-section displays a pronounced peak. We support the conclusion of McAlinden et al.15 and Hewitt et al.14 that above about 4 eV, positronium formation is mainly into excited states. Good agreement is obtained with the total cross-section measurements of Kwan et al.1 and Parikh et al.2 Positronium formation is not important above about 50 eV.

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.

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.

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