Natural Science Forum / Physics / General Physics / July 2008

hi,
    I'm trying to get the basic intuition behind renormalization. Is
it that if I ignore the counterterms in the lagrangian, and calculate
to the first order in the perturbation series, I should get a result
which is as close as possible to the experimental result?

Secondly, if I take a massless particle, and proceed at a
renormalization scale -M^2, it seems totally unphysical.
At least in the massive case, the mass that appears in the Greens
function  (propagator) is the physical mass which can be directly
measured in the experiment.  Hence it has some physical basis.
   In the massless case (with renormalization scale -M^2), the mass
that would appear in the green's function is iM, which has absolutely
no physical basis.  So, any M that one takes is totally arbitrary.
This is something that is troubling me in understanding
renormalization.

thanks
ganesh