I want to use Breit-Wigner formula to calculate the cross section of neutron resonance reaction.
But, in fact, in that formula, there are a lot of parameters I do not know.
Neutron Reaction?
Now, I am doing a research about neutron reaction with many level of energy. With intermediate and high energy, I use optical model to calculate the total cross section of the reaction. But in the low energy, I can not do like that because I do not know about the parameters of...