Can a particle with non-zero rest mass "tunnel" into the tachyon world without having to cross the $m=\infty$ barrier?

Question

In the above diagram, I've indicated the variation of mass of a particle with its velocity using the solid curve for $v < c$ and using the long dashed lines (which lie in the complex plane) for $v > c$.

I know the particle cannot be accelerated to $v >= c$ as its mass reaches infinity when $v$ approaches light speed, but I was just wondering, if it's possible for the particle to somehow "tunnel" into the tachyon world bypassing the barrier (indicated by the curved arrow), especially when the rest mass is low?

If this is, well, physically feasible, what physical process/condition would be a possible candidate that enables such a transition?

Answer 1

Remember, speed is relative: no matter how fast a particle is going relative to you, in its own rest frame its speed is $0$ and the speed of light is $c$. So your hypothetical "tunneling" would, in the initial rest frame of the particle, consist of a particle spontaneously changing from being at rest to being a tachyon. This would appear to violate conservation of momentum, at the very least.