Hello I am reading this book: "[URL [Broken] and the appearance of a classical word&f=false"]decoherence[/URL] I hope someone could help me. Please go to Appendix A1 Joos introduces the notation f(q,q'). What is the dimension of f from his notation? Next page he writes that [tex]\int f^2 d\Omega d\Omega'[/tex] is a cross section. do you understand why?