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 scattering cross sections of positron impact on helium from its metastable state ( ) and ground state along with the CCC results for metastable state ( ). Solid line: metastable state; dashed line: ground state; dotted line: CCC.