Related papers: Low-Energy Scattering Properties of Ground-State a…
The scattering of ortho-positronium (Ps) by hydrogen atoms has been investigated in a five-state coupled-channel model allowing for Ps(1s)H(2s,2p) and Ps(2s,2p)H(1s) excitations using a recently proposed electron-exchange model potential.…
The low-energy scattering of ortho positronium (Ps) by ortho Ps has been studied in a full quantum mechanical coupled-channel approach. In the singlet channel (total spin $s_T=0$) we find S- and P-wave resonances at 3.35 eV (width 0.02 eV)…
We study the $2e^-2e^+$ equal-mass charge-neutral four-body system in the adiabatic hyperspherical framework. The lowest few adiabatic potentials are calculated for zero orbital angular momentum, positive parity, and charge conjugation…
Scattering of positronium (Ps) by sodium and potassium atoms has been investigated employing a three-Ps-state coupled-channel model with Ps(1s,2s,2p) states using a time-reversal-symmetric regularized electron-exchange model potential…
We report results of differential cross sections for elastic scattering, target-elastic Ps excitations and target-inelastic excitation of hydrogen in a five-state coupled-channel model allowing for Ps(1s)H(2s,2p) and Ps(2s,2p)H(1s)…
The elastic and inelastic high--energy small--angle electron--positron scattering is considered. All radiative corrections to the cross--section with the relative accuracy $\delta\sigma/ \sigma = 0.1 \% $ are explicitly taken into account.…
A pseudopotential for positronium-atom interaction, based on electron-atom and positron-atom phase shifts, is constructed, and the phase shifts for Ps-Kr and Ps-Ar scattering are calculated. This approach allows us to extend the Ps-atom…
Cross sections and spin asymmetries for elastic positron scattering and for the emission of positron bremsstrahlung in collision with nuclei of zero and half-integer spin are calculated within the relativistic partial-wave theory. For…
Scattering of positronium (Ps) by helium atom has been investigated in a three-Ps-state coupled-channel model including Ps(1s,2s,2p) states using a recently proposed time-reversal-symmetric regularized electron-exchange model potential.…
The confined variational method is applied to investigate the low-energy elastic scattering of ortho-positronium from $\text{H}_2$ by first-principles quantum mechanics. Describing the correlation effect with explicitly correlated…
Scattering of ortho positronium (Ps) by cesium and rubidium atoms has been investigated employing a three-Ps-state coupled-channel model with Ps(1s,2s,2p) states using a time-reversal-symmetric regularized electron-exchange model potential.…
We present the calculation of the elastic and inelastic high--energy small--angle electron--positron scattering with a {\it per mille} accuracy. PACS numbers 12.15.Lk, 12.20.--m, 12.20.Ds, 13.40.--f
We consider small--angle electron--positron scattering in Quantum Electrodynamics. Leading logarithmic contributions to the cross--section are explicitly calculated to three loop. Next--to--leading terms are exactly computed to two loop.…
The recent theoretical and experimental activities in positronium (Ps) scattering by atoms and molecules are reviewed with special emphasis at low energies. We critically compare the results of different groups $-$ theoretical and…
The scattering of ortho positronium (Ps) by H$_2$ has been investigated using a three-Ps-state [Ps(1s,2s,2p)H$_2($X $^1\Sigma_g^+$)] coupled-channel model and using Born approximation for higher excitations and ionization of Ps and B…
The $s-$wave meson-baryon scattering is analyzed for the isospin-strangeness $I=1/2, S=0$ and $I=0,S=-1$ sectors, in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. For both sectors, four channels have been…
New results are presented for Ps(1s) scattering by H(1s), He(1$^1$S) and Li(2s). Calculations have been performed in a coupled state framework, usually employing pseudostates, and allowing for excitation of both the Ps and the atom. In the…
The low-energy scattering of ortho positronium (Ps) by H, He, Ne, and Ar atoms has been investigated in the coupled-channel framework by using a recently proposed time-reversal-symmetric nonlocal electron-exchange model potential with a…
The coupled-channel model [Phys. Rev. A {\bf 59}, 363 (1999)] that yields converged low-energy phase shifts, and exact binding and resonance features in Ps-H [Phys. Rev. A {\bf 59}, 2058 (1999)] is applied to study Ps-He$^+$ scattering.…
The s-wave scattering length for the Positronium-Positronium interaction is estimated semi-phenomenologically with the long-range van der Waals force and the short-range repulsive potential that represents the hard core between two…