# How to Handle Photon Interactions in Particle Physics?

• nhristov
In summary, there are different techniques for handling particles and antiparticles in particle physics calculations, such as Feynman diagrams and quantum field theory. It's important to carefully read and understand the notation and conventions being used in a problem to successfully solve it.
nhristov
I'm just working on a particle physics assignment and seem to be a little stuck on one concept. I have a positron-electron to two scalar particles and a photon-photon -> electron-positron problem.
The issue I'm having with it is that the only way I really know how to handle them is with the casimir tricks, but the casimir tricks seem to be for when you have for example u'*gamma*u where u and u-bar are an incoming and outgoing fermion and gamma is a matrix.
Is there a different trick to handle the case for having incoming photons rather than an incoming fermion?

Wow, problem solved, I feel silly, antifermions have u-bar for incoming particles rather than outgoing, this is where my issue is. People of the future, read carefully.

Last edited:

Hello there,

I'm glad you were able to solve your problem! It's always important to carefully read and understand the notation and conventions being used in a problem.

To answer your question, there are indeed different techniques for handling particles and antiparticles in particle physics calculations. In the case of incoming photons, you can use Feynman diagrams to represent the interaction between the photons and the particles. The Feynman rules for photon interactions include conservation of energy and momentum at each vertex, and the use of propagators to represent the virtual particles involved in the interaction.

Another technique that can be used is the calculation of scattering amplitudes using quantum field theory. This involves writing down the relevant Lagrangian for the particles involved and using Feynman rules to calculate the amplitude for the given process.

I hope this helps and good luck with your assignment! Keep exploring and learning about particle physics, it's a fascinating field.

## 1. What is particle annihilation and creation?

Particle annihilation and creation refers to the process by which particles and antiparticles interact and produce energy, leading to the creation of new particles.

## 2. How does particle annihilation and creation occur?

Particle annihilation and creation occurs through the annihilation of a particle and its corresponding antiparticle. This results in the conversion of their mass into energy, which can then produce new particles.

## 3. What is the significance of particle annihilation and creation?

Particle annihilation and creation is a fundamental process in quantum physics and has implications in various fields such as cosmology and particle physics. It helps explain the behavior of matter and energy on a subatomic level.

## 4. Can particle annihilation and creation be observed?

Particle annihilation and creation can be observed through experiments such as colliding particle beams or through the detection of high-energy photons produced during the annihilation process.

## 5. Are particle annihilation and creation reversible processes?

Particle annihilation and creation are reversible processes in theory, as particles and antiparticles can be created and annihilated continuously. However, in practice, the energy required to reverse the process is often not feasible.

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