Energy Difference: Antimatter vs Matter

[joychandra]

Suppose an antimatter at lower energy(K.E) collides with a matter in higher energy then what will be the output.

 

[malawi_glenn]

two gamma rays with different energy..

you can always transform it to the centre of momentum frame, so a positron impinging an electron at rest in lab-frame, will result in two back-to-back gamma rays in their centre of mass frame, which you then transform back to the lab frame. Simple relativistic kinematics problem.