- #1

unscientific

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## Homework Statement

A high-energy photon γ

_{1}of energy 261 GeV collides with an infrared photon γ

_{2}of energy 1eV to produce an electron-positron pair via the reaction

γ

_{1}+ γ

_{2}→ e

^{-}+ e

^{+}

## The Attempt at a Solution

Conservation of momentum:

p

_{1}- p

_{2}= (0.5)p

_{e}

But since p

_{1}is 10

^{11}times more than p

_{2},

p

_{e}≈ (0.5)(p

_{1}) = 6.96 x 10-

^{17}kg m s

^{-1}

But when i try to calculate the velocity of the positron/electron using the momentum i get v = c...

__Comparing orders of magnitude__

p

_{e}≈ 10

^{-17}

m(γv) = (10

^{-23}) (γ)

This implies that γ ≈ 10

^{6}...

Am I doing something wrong here?