Number of Spin States of a Graviton?

If spin one bosons have two polarizations like photons, how many polarizations would a spin 2 particle have like a graviton?
- Devon (age 25)
Lansing

Normally, a spin S object will have 2S+1 polarization states.   But for massless particles the transverse modes can't exist due to Lorentz invariance.  Only the positive and negative helicity states remain.  So, the graviton will have only 2 helicity states.   The spin 1 photon is an example of this, it also is restricted to its positive and negative helicity states. Although it is straightforward to observe individual photons, I suspect that individual gravitons will never, ever be observed.  Their interactions are far too weak.  
I tried to find a reasonable explanation for this on the web but was unable to.   There are  quantum field theoretic ones but they are not for the faint of heart: for example--


LeeH

(published on 07/20/2012)