I'm currently learning about the weak nuclear force for my A level, I pretty much understand what's happening in beta decay but I can't see where the W boson is coming from. Example: a neutron comes close to a neutrino. A W+ boson changes one down quark into an up quark, thus changing the neutron in a proton. But where does the W+ boson come from? Is it from the neutrino or just floating around in the air?

no they aren't floating around really. they are virtual particles that only briefly exist, when beta decay occurs. they acquire mass by breaking electroweak symmetry, which happens when the higgs field reaches a certain temperature (due to the unstable nuclear state) and undergoes "tachyon condensation"

the W bozon will exist for like .000000000000000001 seconds and then decay into an electron and electron antineutrino i think

This post was edited by dothe on Aug 17 2012 02:33am