What Processes Occur When Electrons Meet Positrons and Protons?

[neelakash]

Homework Statement

Consider the combination of an electron with positron(I) and an electron with proton(II).The possible processes are:

(i)formation in positronium in (I)
(ii)formation in Hydrogen ataom in (II)
(iii)annihilation of each other and gamma emission in (I) and (II) both
(iv)elastic scatterinh in (I) and (II) both

Homework Equations

The Attempt at a Solution

I think all but (iv) may be correct---elastic scattering should not happen...
Please check.

 

[Gokul43201]

Maybe you should think a little longer about these, particularly 3 and 4.

 

[neelakash]

Possibly (III) is wrong:I mean e and p cannot annihilate but e and positron can

elastic scattering occurs...?

 

[Astronuc]

Electron and positron certainly annihilate producing two 0.511 MeV gammas.

An electron is not annhilated by a proton, but there is a phenomenon called 'electron capture'.

 

[Gokul43201]

elastic scattering occurs...?

Typically, the term elastic scattering is used for events where the loss of energy between the scattered particle and the incident particle is small compared to the incident energy. Rutherford scattering, electron/neutron diffraction, etc. are examples of elastic scattering.