Why Can't Photons Have a Spin of 0 Like Gravitons?

[touqra]

The graviton has a spin of 2. So, that means the graviton can take possible spins: -2, -1, 0, 1, 2 ? Just want to make sure since, for a photon, even if it's spin 1, it can only take two possibilities, i.e. -1 and +1. 0 is not allowed.

 

[dextercioby]

Well, not really. The P-F field has 2 degrees of freedom in 4 space-time dimensions and thus the eigenvalues for the helicity operarator are only +2 and -2.

Daniel.

 

[samalkhaiat]

The graviton has a spin of 2. So, that means the graviton can take possible spins: -2, -1, 0, 1, 2 ? Just want to make sure since, for a photon, even if it's spin 1, it can only take two possibilities, i.e. -1 and +1. 0 is not allowed.

Do you know why the 0 is not allowed for photon? For similar reason the
(-1,0,1) are not allowed for graviton.(massles field,Traceless 2nd rank symmetric tensor rep of Poincare group).


regards

sam