Low-Energy Positron Scattering from H$_{2}$

We present low-energy positron scattering measurements from molecular hydrogen. Our measurements were conducted at the high-resolution, low-energy positron beamline at the Australian National University [1]. The energy width of the positron beam was typically 60 meV. We present results for positron scattering from H$_{2}$ from 1 to 200 eV for the total and positronium formation cross sections as well as total elastic and elastic differential cross sections. Comparison will be made with previous results, in particular recent results of the Trento group [2], along with a discussion of the experimental advantages and limitation of present techniques [3]. The greatest discrepancy between the available experimental and theoretical data sets lies at energies below the positronium formation threshold. A plausible explanation for these differences will be presented.\\[4pt] [1] J. P. Sullivan \textit{et al.},\textbf{79}, 113105 (2008)\\[0pt] [2] A. Zecca \textit{et al.}, Phys. Rev. A \textbf{80}, 032702 (2009)\\[0pt] [3] J. P. Sullivan \textit{et al.}, J. Phys. B \textbf{44}, 035201 (2010)