MEASUREMENTS OF POSITRONIUM-FORMATION CROSS-SECTIONS FOR POSITRONS SCATTERED BY RB ATOMS

Measurements of positronium (Ps)-formation cross sections (upper and l ower limits) for positrons (1-17 eV) scattered by Rb atoms are reporte d. These measurements, along with recent measurements and calculations of total cross sections, provide evidence that coupling effects betwe en Ps formation and other scattering channels may be very important fo r energies below 10 eV for Rb.