Massless boson vs massive boson

[hanks721]

Hi, this might sound stupid, but I have a question.
why does massless bosons, such as photon, gluon have an infinite range where w and z bosons have finite ranges??

 

[Vanadium 50]

The strength of a force goes roughly as $$\frac{e^{-mr}}{r^2}$$ (in units where $$\hbar = c = 1$$). You can see that for a massless boson, it's inverse square, and for a massive boson it falls off faster.