title: Positronium Production and Scattering below Its Breakup Threshold.
abstract: Recent findings on the similarity between electron and positronium scattering at the same velocity [Brawley et al., Science 330, 789 (2010)] have guided us towards the realization of a detectable flux of positronium atoms at beam energies five times lower than previously obtained, enabling total cross sections to be measured in the energy range ∼(1-7)  eV for the first time. In collision with Ar and Xe, the total cross sections of positronium are found to be smallest at the lowest energy probed, approaching those of the Ramsauer-Townsend minima for electron projectiles. Additional structure has been observed in the case of positronium scattering at incident energies around 5 eV.
authors.affiliation: UCL Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: S J
authors.initials: SJ
authors.lastname: Brawley
authors.affiliation: UCL Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: S E
authors.initials: SE
authors.lastname: Fayer
authors.affiliation: UCL Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Shipman
authors.affiliation: UCL Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Laricchia