Hi, so my question is along the lines of the following: Since the strong and EM forces are mediated by massless exchange particles, due to Heisenbergs uncertainty principle these forces are long range. Well, ok. But the weak force is mediated by W and Z bosons which are massive hence they can only get so far before their time is 'ran out', thus short range force. If this is how things work, then is this to say that all exchange particles violate energy conservation, hence the reason when the uncertainty principle has any relevance to the situation? Also, if this is the case, when we have say Higgs=>ZZ=>4 muons, what does it mean to say that one Z boson is real and the other is virtual. Are they not both virtual given that a Z boson is short lived? To my understanding, virtual simply means that the particle is temporary and doesn't have to be created in the final state. Thank you kindly for any responses. I've been really confused about this all day!