A team of scientists set out to find the size of protons, and in doing so have upset the current body of literature on quantum electrodynamics. According to the report published in the journal Science, the scientists used a laser to determine that the radius of a proton is smaller than 0.84087 femtometers, a size so small it is hardly comprehensible without something to put it into perspective.
My own two cents:
Assuming the results are correct, no one should be surprised. After all, it is possible that protons have no size whatsoever. Indeed, it seems likely that this is the case. How, you may ask?
It is certainly possible that protons have no diameter at all. In fact, I would be surprised if they do. What we perceive as diameter isn't a physical property, it's a probability. A proton is probably nothing more than a zero dimensional electrical field. It gives the illusion of diameter because its position is always 'fuzzy', meaning you can never be entirely certain where it is. You can, however, narrow down the possible position to an area where it is most likely to be, and call this area diameter.
The quantum world is a funny place, perched delicately on the border of existence and nonexistence. In very general terms, quantum mechanics describes a bunch of stuff that floats around interfering with each other. Particles are more defined by this interference than inherent properties.