The possible existence of a quasi-bound state of a positron in an electron gas.

Positrons can be used as a probe in the investigation of metals. We intend here to investigate one aspect of their use. We will develop a theoretical description of the interaction of one positron with a sea of electrons. Then with the use of this model we will investigate the possible existence of a quasi-bound state of the positron. Most investigations into annihilation of positrons ignore the possibility of the formation of a quasi-bound state and it's effect on positron lifetime. It is assumed that; a positron introduced into the 'electron gas' will be annihilated from a scattering state