Trace of gamma matrices with FORM

In summary: Your Name]In summary, Pierrechevalier is seeking help with calculating the matrix element of a process using FORM. Despite using the "symmetrize" option, they are encountering issues with thousands of terms containing Levi civita tensors. They have reached out to the community for assistance and have also provided their email for direct contact.
  • #1
pierrechevalier
1
0
Hello everybody,
I have to calculate the matrix element of the process gg-->ttbar-->lnub lnub (ttbar dileptonic decay) using FORM.
I have three feynman dyagrams for such a process. When I calculate the interference term i have as output thousands of terms with Levi civita tensors inside (but with the indeces correctly contracted). I have already used the "symmetrize" option as explained in the tutorial
http://www.nikhef.nl/~form/maindir/documentation/documentation.html
but it doesn't work.
Can someone help me?
It is the first time in this forum, i do not know exactly how it works, so i leave my email
cavaller[at]lpnhe[dot]in2p3[dot]fr
Thanks a lot
Pierrechevalier
 
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  • #2


Dear Pierrechevalier,

Thank you for reaching out to us for help with your calculation. I am a fellow scientist and I would be happy to assist you with your query.

Firstly, I would suggest checking your code for any errors or typos that might be causing the "symmetrize" option to not work properly. It is always a good practice to double check your code and make sure all the necessary steps and options are included.

If the issue persists, I would recommend reaching out to the FORM community for further assistance. They have a dedicated forum and mailing list where experienced users can provide guidance and solutions for specific problems. You can also try searching through their archives to see if anyone has encountered a similar issue in the past.

Additionally, there are also several tutorials and resources available online that can help you with FORM calculations. I would suggest going through these to see if you can find any tips or tricks that might be useful for your specific case.

I hope this helps and wish you all the best with your calculation.
 
  • #3


Hello Pierrechevalier,

Thank you for your question. It seems like you are using FORM to calculate the trace of gamma matrices for the process gg-->ttbar-->lnub lnub. This can be a complex calculation, especially when considering interference terms. It is great that you have already tried using the "symmetrize" option, but it seems like it is not giving you the desired result.

One thing you can try is to use the "contract" option instead of "symmetrize". This should help simplify your output and make it easier to work with. Additionally, make sure that you are using the correct indices when contracting your Levi-Civita tensors.

If you are still having trouble, you can try reaching out to the FORM community for assistance. They have a mailing list where you can ask questions and get help from experienced users. You can also check out their documentation for more information on using FORM for gamma matrix calculations.

I hope this helps. Good luck with your calculation!


 

1. What is FORM in relation to trace of gamma matrices?

FORM is a symbolic manipulation program used in theoretical physics to perform calculations involving trace of gamma matrices. It is specifically designed to handle large algebraic expressions and perform complicated tensor calculations.

2. How does FORM handle trace of gamma matrices?

FORM uses a set of predefined rules and algorithms to simplify the trace of gamma matrices. These rules involve manipulating the gamma matrices according to their algebraic properties and using identities such as the Fierz identity to simplify the expression.

3. Can FORM handle trace of gamma matrices in any dimension?

Yes, FORM has the ability to handle trace of gamma matrices in any dimension. It has built-in functions to deal with arbitrary numbers of gamma matrices and can perform calculations in any number of dimensions.

4. What are the advantages of using FORM for trace of gamma matrices over other programs?

FORM is specifically designed for performing theoretical physics calculations, including trace of gamma matrices. It has a wide range of built-in functions and rules that make it efficient and accurate for handling complicated algebraic expressions. Additionally, FORM has the ability to handle calculations in any number of dimensions, making it a versatile tool for theoretical physicists.

5. Are there any limitations to using FORM for trace of gamma matrices?

While FORM is a powerful tool for handling trace of gamma matrices, it does have some limitations. It may not be suitable for calculations involving more than a few hundred gamma matrices, as the computation time may become too long. Additionally, FORM may not be the best choice for visualizing the results of the calculations, as it primarily focuses on manipulating algebraic expressions rather than producing graphical representations.

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