Question

Why photons are massless but elctron protons neutrons have mass

Answer 1

A massless electron would therefore be at infinity from the proton, not allowing atoms to form at all. ... However, their masses contribute only ~1% of the mass of protons and neutrons. The bulk of the mass comes from the energy holding the quarks together, which is greater for the proton than the neutron.

Answer 2

Answer:

It's because photons do not distort the 4 dimensional space matrix of space.

While other particles like electrons, protons and neutrons distorts.

More the particle distorts the space matrix more will be their mass .