Optical potential approach for positron scattering by metastable 23 S state of helium
Wu Xi-Gang1, Cheng Yong-Jun2, †, Liu Fang3, Zhou Ya-Jun2
       

Total Ps-formation cross sections of positron impact on helium from metastable state ( ) compared with the CCC results [2]. Solid line: present results; dashed line: CCC results.