A new ab initio method of calculating $Z_{eff}$ and positron annihilation rates using coupled-channel T-matrix amplitudes

P K Biswas

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A new ab initio method of calculating $Z_{eff}$ and positron annihilation rates using coupled-channel T-matrix amplitudes

P K Biswas

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Abstract

A new {\it ab initio} theoretical formulation to calculate $Z_{eff}$ and hence the positron annihilation rates is presented using the on-shell and half-offshell T-matrix scattering amplitudes without any explicit use of the scattering wave function. The formulation is exact and universal, as long as the dynamics of the system can be described by a Lippmann-Schwinger type equation. It could serve as an effective tool as all the $T-$, $K-$, and $S-$matrix formulations, yield directly the scattering amplitudes; not the wave function. We also present a basic numerical test of the formulation.

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P K Biswas. 2002-10-29. A new ab initio method of calculating $Z_{eff}$ and positron annihilation rates using coupled-channel T-matrix amplitudes. https://arxiv.org/abs/physics/0210116

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