The tachyon has a spin of 0, does any other particle have a spin of 0?
This I think refers to the tachyon "problem" in string theories, which is the lowest angular momentum particle along the trajectory (so is probably a scalar ).I have trouble with this. First, nobody has seen a tachyon. Second, a spin-1/2 or spin-1 tachyon is no more and no less likely than a spin-0 tachyon.
Ack. Yes. Stupid questions. Tachyons break Lorentz invariance anyway.