In this very specific case, it is not really a matter of fitting. We have a model and the observation of this particle was a prediction. The theory is based on some fundamental principle from which we can deduce a lot of things (predictions) from a very small setter of parameters (fitted quantities).

But there are still unknowns, which we are trying to know better.

Now, how to link this to another domain of science is another question, and exciting too :)