- #1

mathman44

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## Homework Statement

A mass M moving at speed V going east decays into 2 photons. One moves perpendicular (south) and the other at some angle from the horizontal. Show that if tan(theta) = 1/2, then V/C = [sqrt(5)-1] / 2

## The Attempt at a Solution

(gamma is the lorentz factor)

Momentum in x: x momentum of angled photon: gamma*m*v

Momentum in y: y momentum of angled photon = momentum of perpendicular photon = E1/C

Solving for E1, I get mc^2/2*gamma

Since tan(theta) = 1/2 = [P in y]/[P in x]

then 1/2 = [E1/C]/[gamma*m*v]

I get V = C/gamma^2...