There's no evidence to suggest that tachyons exist, and rather a lot to suggest they don't.
The idea of tachyons didn't come out of any sort of research. They basically came from some bloke thinking "well, if there are particles that always move slower than light, and particles that always move at the speed of light, could there be particles that always move faster than light?"
It's a neat idea, but alas, the nature of physics seems to suggest the answer is a resounding "no."
One big problem with the notion that anything--matter or information--can move faster than light is the problem that, because motion is always relative, if it's possible to move faster than light, it's always possible to create an inertial frame such that causality is violated. Or, to put it less technically, there is no functional difference between traveling faster than light and time travel.
