Both rest masses of photon and graviton are zeros. Again, accepted by all quantum field theorists.
Those theorists haven't quantized gravity yet despite all their theories!
It is assumed that a photon is massless but what do we mean by mass.
Inertial mass or gravitational mass?
A photon has gravitational mass because it is deflected by the Sun.
Inertial mass is supposed to be the same as gravitational mass.
So why can't a photon have inertial mass too?
Because special relativity says that it has zero rest mass?
It seems more likely to me that special relativity has got something missing from it.
If positrons and electrons which have rest mass can become photons, why should the rest mass disappear?
When an electron is accelerated it gains relativistic mass and it should take an infinite force to get it to move at the speed of light.But what if the limiting speed of a particle can be determined by its spin.What if an electron has a permanent short-range magnetic field (that exists at constant velocityand has so far eluded experimental detection) and I changed the spin of an electron from 1/2 to 1 by changing the ratio of the electric to magnetic fields so E / Bfor an electron = 10^8 m/s.