scholarly journals Study of Positron Impact Scattering from Methane and Silane Using an Analytically Obtained Static Potential with Correlation Polarization

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 113
Author(s):  
Dibyendu Mahato ◽  
Lalita Sharma ◽  
Rajesh Srivastava
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
Theoretical Calculations ◽  
Model Potential ◽  
Positron Impact ◽  
Static Potential ◽  
Total Cross Sections ◽  
Atomic Orbitals ◽  
Shift Analysis ◽  
Molecular Wavefunctions

A detailed study of positron impact elastic scattering from methane and silane is carried out using a model potential consisting of static and polarization potentials. The static potential for the molecular target is obtained analytically by using accurate Gaussian molecular wavefunctions. The molecular orbitals are expressed as a linear combination of Gaussian atomic orbitals. Along with the analytically obtained static potential, a correlation polarization potential is also added to construct the model potential. Utilizing the model potential, the Schrödinger equation is solved using the partial wave phase shift analysis method, and the scattering amplitude is obtained in terms of the phase shifts. Thereafter, the differential, integrated and total cross sections are calculated. These cross-section results are compared with the previously reported measurements and theoretical calculations.

scholarly journals Study of Electron and Positron Elastic Scattering from Hydrogen Sulphide Using Analytically Obtained Static Potential

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 83
Author(s):  
Dibyendu Mahato ◽  
Lalita Sharma ◽  
Rajesh Srivastava
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Hydrogen Sulphide ◽  
Analytical Form ◽  
Present Approach ◽  
Positron Impact ◽  
Static Potential ◽  
Positron Scattering ◽  
Shift Analysis ◽  
Gaussian Orbitals

A detailed study of elastic scattering of electrons and positrons from a hydrogen sulphide (H2S) molecule is presented using the method of partial wave phase shift analysis with suitably chosen complex optical potentials. The important aspect of our present work is that we uniquely obtain static potential in an analytical form and use it along with exchange (only for electron), polarization and purely imaginary absorption potentials to define the complex optical potential. The static potential is evaluated by obtaining charge density from the H2S molecule using the molecular wavefunction represented through an accurate analytical form of the Gaussian orbitals. The primary aim of our study is to test our present approach, as applied to the electron and positron scattering from H2S. Therefore, the results for electron and positron impact differential, integral, momentum-transfer, absorption and total cross sections are obtained for the incident energies in the range of 10–500 eV. Comparisons of these different types of cross section results with the available measurements and other calculations show good agreement, which suggests the applicability of our present approach.

PION-NUCLEON SCATTERING EXPERIMENTS AT LOW ENERGIES: π-p→π0n TOTAL CROSS SECTIONS

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1818-1821
Author(s):  
J. BREITSCHOPF ◽  
M. BAUER ◽  
H. CLEMENT ◽  
M. CRÖNI ◽  
H. DENZ ◽  
...  
Keyword(s):  
Phase Shift ◽  
Cross Sections ◽  
Phase Shift Analysis ◽  
Single Charge ◽  
Charge Exchange Reaction ◽  
Total Cross Sections ◽  
Transmission Technique ◽  
Shift Analysis ◽  
Low Energies ◽  
Pion Nucleon

Total cross sections of the single charge exchange reaction π-p→π0n have been measured at PSI from about 40 to 250 MeV using a transmission technique. Preliminary results show an excellent agreement with predictions from the SAID FA02 phase shift analysis for energies above 70 MeV.

scholarly journals Total Electron Scattering Cross Sections of He, Ne, Ar, Kr and Xe in the Energy Range 100 eV to 10 000 eV

2009 ◽  
Vol 64 (9-10) ◽  
pp. 665-670
Author(s):  
Xiao-Ming Tan ◽  
Chuan-Lu Yang ◽  
Mei-Shan Wang ◽  
Zhi-Hong Zhang
Keyword(s):  
Energy Range ◽  
Electron Scattering ◽  
Cross Sections ◽  
Model Potential ◽  
Total Electron ◽  
Total Cross Sections ◽  
Optical Model Potential ◽  
Scattering Cross Sections ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

The total cross sections for electron scattering from He, Ne, Ar, Kr and Xe in the energy range from 100 eV to 10 000 eV have been calculated based on the optical-model potential. Our theoretical results are compared with the available experimental data. The consistency between them is also discussed. At higher energies (over 2000 eV for He, over 5000 eV for Ne, Ar, Kr and Xe), the total cross sections of electron scattering from these atoms are scarce, so our calculations will give a reference for further experimental and theoretical studies.

Discrepancy in total cross sections of positron-impact ionization of hydrogen

1992 ◽  
Vol 167 (3) ◽  
pp. 277-279 ◽  
Author(s):  
Shih-Wei Hsu ◽  
Tien-Yow Kuo ◽  
Chi-ming J. Chen ◽  
Keh-Ning Huang
Keyword(s):  
Cross Sections ◽  
Impact Ionization ◽  
Positron Impact ◽  
Total Cross Sections

scholarly journals KN scattering amplitude revisited in a chiral unitary approach and a possible broad resonance in S = +1 channel

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Kenji Aoki ◽  
Daisuke Jido
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
Resonance State ◽  
Model Parameters ◽  
Broad Resonance ◽  
Total Cross Sections ◽  
Unitary Approach ◽  
Unitary Model ◽  
Chiral Unitary Approach ◽  
Energy Plane

Abstract We revisit the $KN$ scattering amplitude in order to investigate the possibility of the existence of a broad resonance in the $I=0$$KN$ channel around the energy of 1617 MeV with 305 MeV width. We use the chiral unitary model to describe the $KN$ scattering amplitudes and determine the model parameters so as to reproduce the differential cross sections of the $K^{+}N$ scatterings and the $I=0$ and 1 total cross sections up to $p_{\rm lab} = 800$ MeV/c, from which inelastic contributions start to be significant. Performing analytic continuation of the determined amplitude to the complex energy plane, we find a pole for a broad resonance state. We point out that the rapid increase appearing in the $I=0$ total cross section around $p_{\rm lab}=500$ MeV/c is a hint of the possible broad resonance of strangeness $S=+1$.

scholarly journals Some Recent Results on High-Energy Proton Interactions

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 57-69 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
High Energy ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Energy Proton ◽  
Elastic Scattering Amplitude ◽  
Energy Behavior ◽  
Impact Parameter Space ◽  
The Impact

Recent experimental results about the energy behavior of the total cross sections, the share of elastic and inelastic contributions to them, the peculiar shape of the differential cross section and our guesses about the behavior of real and imaginary parts of the elastic scattering amplitude are discussed. The unitarity condition relates elastic and inelastic processes. Therefore it is used in the impact-parameter space to get some information about the shape of the interaction region of colliding protons by exploiting new experimental data. The obtained results are described.

scholarly journals GAUGE/STRING-GRAVITY DUALITY AND FROISSART BOUND

2005 ◽  
Vol 20 (06) ◽  
pp. 1286-1294
Author(s):  
KYUNGSIK KANG
Keyword(s):  
Cross Sections ◽  
Particle Physics ◽  
Scattering Amplitude ◽  
Conformal Symmetry ◽  
High Energy ◽  
Total Cross Sections ◽  
Regge Behavior ◽  
Energy Behavior ◽  
Gravity Duality ◽  
String Gravity

The gauge/string-gravity duality correspondence opened renewed hope and possibility to address some of the fundamental and non-perturbative QCD problems of in particle physics, such as hadron spectrum and Regge behavior of the scattering amplitude at high energies. One of the most fundamental and long-standing problems is the high energy behavior of the total cross-sections. According to a series of exhaustive tests by the COMPETE group, (1) total cross sections have a universal Heisenberg behavior in energy corresponding to the maximal energy behavior allowed by the Froissart bound, i.e., A+B ln 2(s/s0) with B~0.32 mb and s0~34.41 GeV2 for all reactions, and (2). The factorization relation among σpp,even, σγp and σγγ is well satisfied by experiments. I discuss the recent interesting application of the gauge/string-gravity duality of AdS/CFT correspondence with a deformed background metric so as to break the conformal symmetry that lead to the Heisenberg behavior of rising total cross sections, and present some preliminary results on the high energy QCD from Planckian scattering in AdS and black-hole production.

Measurements of total and (or) positronium-formation cross sections for positrons scattered by alkali, magnesium, and hydrogen atoms

1996 ◽  
Vol 74 (7-8) ◽  
pp. 313-333 ◽  
Author(s):  
T. S. Stein ◽  
J. Jiang ◽  
W. E. Kauppila ◽  
C. K. Kwan ◽  
H. Li ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Positronium Formation ◽  
Projectile Energy ◽  
Hydrogen Atoms ◽  
Positron Energy ◽  
Total Cross Sections ◽  
Alkali Atoms ◽  
Low Energies

Recent developments in measurements of total and (or) positronium-formation cross sections for positrons (in the range of 1 to 300 eV) scattered by alkali, magnesium, and hydrogen atoms are reviewed. Measurements of total and positronium (Ps)-formation cross sections for positrons scattered by sodium, potassium, and rubidium have revealed an interesting pattern of differences and similarities between these collision systems. These measurements, together with recent calculations, provide evidence that coupling effects between Ps formation and other scattering channels are very important at low energies for the alkali atoms. The calculations also indicate that formation of Ps in excited states in the cases of potassium and rubidium is more likely than formation in the ground state when the positron energy is greater than about 5 eV. Measurements of total and Ps-formation cross sections for positrons scattered by magnesium are in a preliminary stage, but the differences between them and the results of available theoretical calculations are providing a strong incentive to intensify experimental and theoretical investigations of this collision system. Refinements in a recently developed technique for measuring total cross sections for positrons and electrons scattered by atomic hydrogen have led to preliminary new results for these systems that are in very good agreement with recent theoretical calculations. These measurements, together with the calculations with which they agree, indicate that as the projectile energy is increased through the higher energy range (above 50 eV), the total cross sections for positrons approach the corresponding results for electrons from above, which is the reverse of the relationship between the positron and electron total cross sections in this energy range for all of the room-temperature gases that have been investigated, except possibly for molecular hydrogen.

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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