Tachyons have never been found in experiments as real particles traveling through the vacuum, but we predict theoretically that tachyon-like objects exist as faster-than-light 'quasiparticles' moving through laser-like media. ... "We are beginning an experiment at Berkeley to detect tachyon-like quasiparticles.

What if tachyons were real?

In Einstein's theory of special relativity, only massless particles like the photon travel at the speed of light; all other particles travel slower. The existence of tachyons can lead to “time travel” paradoxes. ... If tachyons were electrically charged, they could produce Cherenkov radiation in empty space.

Who found tachyon?

Tachyons were first introduced into physics by Gerald Feinberg, in his seminal paper "On the possibility of faster-than-light particles" [Phys. Rev. 159, 1089—1105 (1967)]. E = m[1−(v/c)²]^−½.