What´s the difference between a resonance and a virtual state? For comparison, a standard moderately lived state, hydrogen 2p state, has energy of 10,2 eV above ground, and width 4*10ˇ-7 eV. An example of resonance is Delta - with mass 1232 MeV, it´s energy is about 290 MeV above ground (nucleon) and width around 110 MeV. And then there are virtual states, like virtual paradeuteron. Paradeuteron is supposed to be a state unbound by around 60 keV, and is very important for proton-neutron scattering. What is technical difference then comparing a resonance with a virtual state?