Solving Problem 10.3 from Peskin's QFT Book

[phinlamp]

Hi,

I'm stuck with problem 10.3 from Peskin's QFT book. I'm trying to evaluate the 2-loop sunset diagram in massless phi^4 theory however I keep running into trouble. I'm trying to use standard feynman parameter + dimensional regularisation techniques however i keep getting stuck when it comes to integrating over the 2nd loop.

Can anyone help me?

Phin

 

[dextercioby]

How about you post the integral which gives u headaches...?Do u use a generalized zeta Riemann regularization...?

Daniel.

 

[sir-pinski]

Hi Phin,

I understand your frustration with this problem. Evaluating the 2-loop sunset diagram in massless phi^4 theory can be quite tricky. One approach you can try is to use the method of integration by parts, where you integrate over one loop at a time and then use integration by parts to simplify the resulting integrals. Another technique you can use is to expand the integrand in terms of small parameters and then use perturbation theory to evaluate the integral. Finally, you can also try using computer software such as Mathematica to help with the calculations.

I hope these suggestions are helpful and that you are able to successfully solve the problem. Don't get discouraged, sometimes these problems can take time and effort to figure out. Keep persisting and I'm sure you will eventually find a solution. Best of luck!