Eur. Phys. J. D 37, 151-152 (2006)
https://doi.org/10.1140/epjd/e2005-00322-3

Comment

Have positron-helium scattering resonances been observed?

Hydrogen, Environment and Energy Laboratory, Department of Physics, University of Trento, 38050 Povo (TN), Italy

Received: 22 September 2005
Published online: 6 December 2005

Abstract

We comment on the recent claim by Karwasz [Eur. Phys. J. D 35, 267 (2005)] that he observed resonant structures in the total cross-section for positron scattering from helium. We frame our observations in terms of both the general capabilities of the Trento spectrometer, and new checks we have made on the measurement procedure employed by Karwasz. We conclude that the observed structures are most likely an experimental artefact, rather than being due to the positron-helium interaction.