Inside the Proton
This should be required reading for this article:<p><a href="https://profmattstrassler.com/2022/09/09/protons-and-charm-quarks-a-lesson-from-virtual-particles/" rel="nofollow">https://profmattstrassler.com/2022/09/09/protons-and-charm-q...</a><p>Virtual particles do not necessarily have an invariant mass. That's why you can find examples of typically huge particles inside protons. That's why a beta decay of a neutron can involve the production of a virtual W- boson that has an invariant mass that's 86 times more massive than the neutron.