With a mean life time of E-25s for the W an Z bosons and E-22s (predicted) for the Higgs boson nobody has directly observed these particles why these particles are not categorized as virtual particles?
Also with such a short lifetime there is no way to find out if their mass is inertial and even measure their linear speed.
For example the Z boson is the only neutral elementary particle (except the Higgs) boson of spin 1 without charge resembling strongly the photon and and the gluon which have also spin 1 and charge 0, but strangely opposite to the photon and gluon, has mass? Why?
What is this mass for the Z boson literature is referring to? Is is a E=mc^2 equivalent mass assigned to it to characterize its energy or is real inertial mass?
Do experiments exist which actually measured the linear speed of the Z boson? I can not find any in the literature. If it is found to travel with the speed of light that would mean that it has no inertial mass but only energy momentum like the photon.
It is hard for me to believe that an elementary particle with spin 1 and zero charge could ever have real mass (inertial).
I believe that we have to stop to attribute spin and charge to virtual particles like these which are not stable in nature.