Experimental determination of the scattering length for positron scattering from krypton

Abstract

We report the first experimentally supported determination of the scattering length for positron scattering from krypton. Our result of -10.3 ± 1.5 a.u. compares favourably with that from a convergent close coupling calculation performed as a part of this investigation (-9.5 a.u.), and also with an earlier many body theory calculation of -10.1 a.u. from Gribakin and Ludlow [Phys. Rev. A 70, 032720 (2004)] and a polarized-orbital result of -10.4 a.u. from McEachran et al. [J. Phys. B 13, 1281 (1980)]. The present experimental scattering length supports the existence of a low-lying positron-krypton virtual state (Surko et al. [J. Phys. B 38, R57 (2005)]) at an energy ε = 0.13 eV.