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.

scholarly journals Formation of non-excited and excited hydrogen in proton–lithium inelastic scattering

2016 ◽  
Vol 94 (1) ◽  
pp. 75-78 ◽  
Author(s):  
S.A. Elkilany ◽  
A.A. Al-Dhawi
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Lithium Atom ◽  
Basis Functions ◽  
Hydrogen Formation ◽  
Electron Model ◽  
Static Approximation ◽  
Total Cross Sections ◽  
First Time ◽  
Good Agreement

The collisions of a proton with a lithium atom are treated for the first time as a three-channel problem under the assumption that the elastic and hydrogen formation in non-excited, H(1s), and excited, H(2s), channels are open. The effect of polarization potentials of the target and hydrogen formation is considered. A one-valence-electron model for the target, based on the Clementi–Roetti Slater-type basis functions, as well as a modified coupled-static approximation are used to calculate the partial and total cross sections of seven partial waves (0 ≤ ℓ ≤ 6, where ℓ is the total angular momentum) at incident energies between 50 and 500 keV. Our values of the total cross section are in good agreement with previous results.

A possible pomeron building mechanism in the fragmentation region

1978 ◽  
Vol 56 (9) ◽  
pp. 1142-1149
Author(s):  
C. G. Georgalas ◽  
P. H. Papargyropoulos
Keyword(s):  
Integral Equation ◽  
Cross Section ◽  
Cross Sections ◽  
Inclusive Cross Section ◽  
High Energy ◽  
Fragmentation Region ◽  
Total Cross Sections ◽  
Energy Hadron ◽  
The One ◽  
Good Agreement

By the use of a Regge parametrization of the one-particle inclusive cross section in the fragmentation region, an integral equation is obtained for the high-energy hadron–hadron inelastic cross section. The main assumptions used in the derivation of this integral equation are: (i) When two hadrons collide with sufficiently high energy, the elastic, inelastic, and total cross sections have the same energy dependence and (ii) Unitarity and factorization of Regge residues hold also for Reggeon–hadron 'amplitudes'. The solution of the integral equation, i.e., the function σinel(s) can be made constant or slowly increasing. For 'reasonable' values of all the parameters involved, it is in very good agreement with the high energy pp data.

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.

TOWARDS THE DETERMINATION OF THE π-p → f2(1270)n REACTION CROSS-SECTION

1993 ◽  
Vol 08 (25) ◽  
pp. 2343-2350 ◽  
Author(s):  
N. N. ACHASOV ◽  
G. N. SHESTAKOV
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Reaction Cross Section ◽  
Branching Ratios ◽  
Reaction Cross ◽  
Precise Estimation ◽  
The One ◽  
Reaction Cross Sections

In this letter, the necessity of a more precise estimation of the data on the reaction π-p → f2(1270)n → π0π0n is mentioned. The total cross-section σ(π-p → f2(1270)n) obtained from the data on the reaction π-p → π0π0n is shown to be approximately three times smaller than that following from the π-p → π+π-n data and also four times smaller than the prediction of the one-pion-exchange model. It is very important to resolve this disagreement because the results on the reaction π-p → f2(1270)n → π0π0n are used directly for the normalization of other reaction cross-sections and determination of branching ratios for some resonances.

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.

Modeling $\bar{p}p$ and recent LHC pp total cross-sections

2014 ◽  
Vol 29 (08) ◽  
pp. 1450044 ◽  
Author(s):  
Amr Radi ◽  
Esraa El-Khateeb
Keyword(s):  
Neural Network ◽  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Hadron Collider ◽  
Center Of Mass ◽  
High Energy ◽  
Ann Model ◽  
Predicted Values ◽  
Good Agreement

New technique is presented for modeling total cross-section of both pp and [Formula: see text] collisions from low to ultra high energy regions using an efficient artificial neural network (ANN). We have used the input (center-of-mass energy, [Formula: see text], and type of particle P) and output (total cross-section σ tot ) data to build a prediction model by ANN. The neural network has been trained to produce a function that studies the dependence of σ tot on [Formula: see text] and P. The trained ANN model shows a good performance in matching the trained distributions, predicts cross-sections that are not presented in the training set. The general trend of the predicted values shows a good agreement with the recent Large Hadron Collider (LHC) measurements, where the total cross-section at [Formula: see text] and 8 TeV are measured to be 98.6 mb and 101.7 mb, respectively. The predicted values of the total cross-section at [Formula: see text] and 14 TeV are found to be 105.8 mb and 111.7 mb, respectively. Those predictions are in good agreement with Block, Cudell and Nakamura.

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 Low Energy Electron Scattering From H2

1990 ◽  
Vol 43 (5) ◽  
pp. 665 ◽  
Author(s):  
MJ Brunger ◽  
Stephen J Buckman ◽  
DS Newman
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Cross Sections ◽  
Incident Energy ◽  
Vibrational Excitation ◽  
Elastic Electron Scattering ◽  
Total Cross Sections ◽  
Threshold Excitation ◽  
Low Energy Electron ◽  
Good Agreement

Absolute differential and integrated total cross sections for elastic electron scattering and vibrational excitation of molecular hydrogen have been measured at an incident energy of 1�5 eV. The results are presented and discussed with particular reference to a long-standing impasse which has existed between and within experiment and theory for the near-threshold excitation of the first vibrational state of H2. The integral vibrational cross section is in good agreement (�10%) with previous beam experiments and theory but is some 60% higher than the cross section derived from a swarm analysis.

Electron Excitation of 21S, 23S, 21P, and 23P States of Helium

1975 ◽  
Vol 53 (20) ◽  
pp. 2289-2295 ◽  
Author(s):  
H. G. P. Lins de Barros ◽  
H. S. Brandi
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Scattering Amplitude ◽  
Theoretical Calculations ◽  
Electron Excitation ◽  
Wave Functions ◽  
Excitation Cross Sections ◽  
Characteristic Values ◽  
The One

Calculations for the total excitation cross sections of the 21S, 23S, 21P, and 23P states of He by electron impact have been carried out assuming the Born–Ochkur approximation for the scattering amplitude and a parametrization previously proposed by the authors for the total cross section. For the atomic wave functions we used LS coupling and obtained the one electron orbitals using the Xα method for three characteristic values of the parameter α. The results are compared with other experimental and theoretical calculations.

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