High-precision quantum-mechanical calculations have been developed to investigate positronium (Ps) scattering. Positronium scattering experiments are a powerful tool to study positronium-matter interactions, but the theoretical description of these experiments needs better accuracy. We have developed an ab initio confined variational approach that can reach higher collision energy, includes higher orbital momenta and uses small confining radii. Calculation of the Ps-He momentum-transfer cross section shows that the experimental Doppler broadening spectroscopy results are questionable. The energy dependence of the pickoff annihilation rate is also calculated, demonstrating an important role of the so far neglected P-wave contribution.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: M.-S.W. was supported by the National Natural Science Foundation of China under Grant No. 11704399. J.-Y.Z. was supported by the “Hundred Talents Program” of the Chinese Academy of Sciences. Z.-C.Y. was supported by the NSERC of Canada and in part by the Chinese Academy of Sciences within the CAS/SAFEA International Partnership Program for Creative Research Teams. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). The authors
are thankful for the computational resources provided by the ACEnet of Canada.