Title : Positron-helium scattering at medium energies using 
        close-coupling approximation
Authors : Puspitapallab Chaudhuri and Sadhan K adhikari 
Affiliations : Instituto de F\'isica Te\'orica, UNESP,
               01405-900, s\~ao Paulo, S\~ao Paulo, Brazil
Summary : Elastic, excitation and positronium formation processes
          in positron-helium scattering have been investigated 
using the close-coupling approximation with realistic wave functions
employing the following states : He(1s1s), He(1s2s), He(1s2p), 
He(1s3s), He(1s3p), Ps(1s), Ps(2s) and Ps(2p). Results are compared
with other theoretical and experimental studies. The present 
cross sections are in good agreement with experimental results.