(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

This is the last problem I'll trouble you guys with, I'm just completely stuck on it. Here it is.

In the jet of a quasar, an ultr&relativistic electron collides head-on with a very

low energy photon of the cosmic microwave background. No new particles are created.

Show that the energy of the photon after the collision is given by

E= (El + P1*C)E2

(El - Pl*C) + 2E2

where E1 and p1 are respectively the energy and the magnitude of the momentum of

the incident electron, and E2 is the energy of the initial photon.

2. Relevant equations

Call mass of the electron m

Obviously that e^2-p^2c^2 = 0 for a photon

3. The attempt at a solution

So far I've worked out that (E1 + E2)^2 - (p1 + E2/C)^2 = (from the cm frame invarient of the square of the resultant rest masses) (mC^2)^2 = E1^2 - (p1C)^2.

Very nice, but whenever I try to introduce a final value of E for the finishing energy of the photon, I get stuck, and cannot elimiate enough variables.

Any ideas?

Cheers

Cpfoxhunt

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# Homework Help: One Final Special Relativity collision problem (no new particles created)

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