Rational polynomial approximants and scattering amplitude for long range potentials

1976 ◽  
Vol 277 (1) ◽  
pp. 1-7 ◽  
Author(s):  
O. D. Corbella ◽  
C. R. Garibotti ◽  
F. F. Grinstein
Keyword(s):  
Long Range ◽  
Scattering Amplitude ◽  
Rational Polynomial

scholarly journals Tidal effects for spinning particles

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Rafael Aoude ◽  
Kays Haddad ◽  
Andreas Helset
Keyword(s):  
Long Range ◽  
Weyl Tensor ◽  
Hilbert Series ◽  
Scattering Amplitude ◽  
Tidal Effects ◽  
Scattering Angle ◽  
Spinning Particles ◽  
Scalar Particles ◽  
Point Particles ◽  
Spin Scattering

Abstract Expanding on the recent derivation of tidal actions for scalar particles, we present here the action for a tidally deformed spin-1/2 particle. Focusing on operators containing two powers of the Weyl tensor, we combine the Hilbert series with an on-shell amplitude basis to construct the tidal action. With the tidal action in hand, we compute the leading-post-Minkowskian tidal contributions to the spin-1/2–spin-1/2 amplitude, arising at $$ \mathcal{O} $$ O (G2). Our amplitudes provide evidence that the observed long range spin-universality for the scattering of two point particles extends to the scattering of tidally deformed objects. From the scattering amplitude we find the conservative two-body Hamiltonian, linear and angular impulses, eikonal phase, spin kick, and aligned-spin scattering angle. We present analogous results in the electromagnetic case along the way.

A HYPOTHETICAL, ATTRACTIVE LONG-RANGE FORCE FROM TWO-GLUON EXCHANGE, AND THE MEASUREMENT OF ρ IN HIGH ENERGY $\bar p p$ ELASTIC SCATTERING

1994 ◽  
Vol 09 (20) ◽  
pp. 1835-1844 ◽  
Author(s):  
S. BARSHAY ◽  
J.A. GRIFOLS ◽  
S. TORTOSA
Keyword(s):  
Elastic Scattering ◽  
Long Range ◽  
Scattering Amplitude ◽  
High Energy ◽  
Small Momentum ◽  
Energy Formula ◽  
Nuclear Amplitude ◽  
Energy Bar ◽  
Coulomb Amplitude ◽  
Range Force

The dynamical question is raised of the possible existence of long-range, residual attractive forces between hadrons due to the overall color-neutral exchange of two, massless transverse gluons between their constituents. Such a force between fermionic constituents would behave as 1/R6. We discuss the experiments which measure the real part of the nuclear amplitude, through its interference with the Coulomb amplitude in high energy [Formula: see text] elastic scattering at very small momentum transfers. We show that on-going [Formula: see text] experiments at [Formula: see text] and at 1800 GeV are sensitive to the scattering amplitude from a residual long-range force.

Velocity Dependence of the Scattering Amplitudes in Resonant Collisions

1972 ◽  
Vol 50 (11) ◽  
pp. 1175-1181 ◽  
Author(s):  
H. R. Zaidi
Keyword(s):  
Scattering Amplitudes ◽  
Long Range ◽  
Relative Velocity ◽  
Short Range ◽  
Scattering Amplitude ◽  
Forward Scattering ◽  
Repulsive Core ◽  
Velocity Dependence ◽  
Forward Scattering Amplitude ◽  
Resonance Broadening

The forward scattering amplitude for the two-body resonant collision is calculated as a function of the relative velocity. The interaction is assumed to be the long-range dipole–dipole, together with a short-range repulsive core. The quantum as well as semiclassical calculations are performed, and the validity of the existing calculations is discussed. Application of the results to the problem of resonance broadening is considered in detail.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Single Atom Image Contrast in Fixed Beam Dark Field Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 366-367
Author(s):  
Wah Chi
Keyword(s):  
Scattering Amplitude ◽  
Present Report ◽  
Dark Field ◽  
Image Contrast ◽  
Single Atom ◽  
Optical Theorem ◽  
Hartree Fock ◽  
Heavy Atoms ◽  
Beam Stop ◽  
Fixed Beam

Resolution and contrast are the important factors to determine the feasibility of imaging single heavy atoms on a thin substrate in an electron microscope. The present report compares the atom image characteristics in different modes of fixed beam dark field microscopy including the ideal beam stop (IBS), a wire beam stop (WBS), tilted illumination (Tl) and a displaced aperture (DA). Image contrast between one Hg and a column of linearly aligned carbon atoms (representing the substrate), are also discussed. The assumptions in the present calculations are perfectly coherent illumination, atom object is represented by spherically symmetric potential derived from Relativistic Hartree Fock Slater wave functions, phase grating approximation is used to evaluate the complex scattering amplitude, inelastic scattering is ignored, phase distortion is solely due to defocus and spherical abberation, and total elastic scattering cross section is evaluated by the Optical Theorem. The atom image intensities are presented in a Z-modulation display, and the details of calculation are described elsewhere.

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