# Photon-electron collision with pair production

• WrongMan
In summary, when a photon collides with an electron, it produces an electron-positron pair. The three particles move together in the same direction and can be described using relativistic formulas for energy and momentum. The correct answer can be found by using the formula ##E^2 = m^2 c^4 + p^2 c^2## without introducing velocity.
WrongMan

## Homework Statement

photon collides with an electron producing a electron-positron pair, the three particles ( two electrons and one positron) move together in the same direction of the original photon.
calculate the energy of each particle.

## Homework Equations

photon:
Ep=hf
p=E/c
electron/positron
1) E=Ke+me*c^2

## The Attempt at a Solution

so 2)Ep + me*c^2=3E : photon energy plus electron rest energy equals the energy of the 3 remaining particles and since mass and direction is the same the energy is the same, same goes for momentum
3)Ep/c=3p
so 2 equations 3 unkowns so i wrote eq 2) with 1) and substituted k for 1/2*me*v^2 and in eq 3) i substituted p for me*v, this did not yield a correct answers.
how should i do this?

You cannot use the nonrelativistic kinetic energy and momentum formulas here. The particles will move at significant speed. You have to use the relativistic formulas.

WrongMan
mfb said:
You cannot use the nonrelativistic kinetic energy and momentum formulas here. The particles will move at significant speed. You have to use the relativistic formulas.
so K= m*c2*(1/(1-v2/c2)0.5)-m*c2
and p=m*v*(1/(1-v2/c2)0.5)
thanks!

I wouldn't introduce the velocity at all. ##E^2 = m^2 c^4 + p^2 c^2##

WrongMan
ok! got the correct answer now... thanks!

## What is a photon-electron collision with pair production?

A photon-electron collision with pair production is a type of interaction between a photon (a particle of light) and an electron. This interaction can result in the creation of a pair of particles, typically an electron and its antiparticle, such as a positron.

## How does pair production occur in a photon-electron collision?

In a photon-electron collision, the energy of the photon is converted into mass, resulting in the creation of a pair of particles. This process follows the equation E=mc^2, where E is the energy of the photon, m is the mass of the particles created, and c is the speed of light.

## What is the significance of pair production in physics?

Pair production plays an important role in understanding the behavior of particles and the fundamental forces of nature. It is also a crucial process in the creation of matter in the early universe and in high-energy particle collisions, such as those that occur in particle accelerators.

## What are the potential applications of photon-electron collisions with pair production?

Photon-electron collisions with pair production have potential applications in medical imaging, such as positron emission tomography (PET) scans, and in the development of new technologies, such as gamma-ray telescopes.

## What are the current research efforts in the field of photon-electron collisions with pair production?

Current research in this field focuses on understanding the underlying mechanisms of pair production and its applications, as well as exploring new ways to manipulate and control this process for various purposes. Some areas of interest include studying the effects of strong magnetic fields on pair production and investigating ways to increase the efficiency of this process.

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