What happened to the idea of tachyonic or other superluminal neutrinos? While hunting around for information about the recent OPERA measurement that hints at superluminal neutrinos, I discovered that this idea was actually considered back in the 1980s. Wikipedia lists as references two papers by Chodos et al. (unfortunately they're paywalled so I can't access them right now), and some more recent ones dealing with the Standard Model Extension.
I'm curious: what happened to this line of inquiry? Did it get conclusively disproven at some point, or just ignored because there was never any reason to believe that tachyons exist? Or are there still people doing legitimate research on it?
 A: Yes a few people wrote papers looking a tachyonic/superlumminal in the 1990s after experiments measuring the mass squared of a neutrino from tritium decay. Tritium decays with a fixed total energy into a neutrino an electron and helium-3, by the measuring the maximum energy of the electron and subtracting, you get the minimum energy of a neutrino and thus its mass. It turned out the neutrino actually seemed to have negative squared mass, (tachyonic), but this was totally within the error bars,e.g. m_{nu}^{2}=-0.67+/- 2.53 {eV}^{2}, at the Troitsk experiment. The error bar is much bigger than the data point, so it was pretty much ignored. But a number of papers where written, and several other experiment also showed negative squared mass data points.
Neutrinos have also been looked at for tachyonic behaviour because of the chiral nature. Since there only left handed neutrino, and right handed anti-neutrino (that a known so far, experiment might find sterile revered version of the known ones). This means that when the vacuum creates a neutrino anti-neutrino pair, back to back emission so opposite momentum, that the total has a spin 1. For any non-chiral particles the spin could be zero, meaning that the vacuum would decay, if the particle could exist with negative energy. But the chiral nature of the neutrino means this can't happen, and the vacuum is safe even with
tachyonic neutrinos. 
The small tachyonic masses (can I say measured, that would be wrong, clearly any random measurement around zero, would find a negative number half the time), however don't match
the -(120 MeV) squared needed to fit the OPERA result using tachyonic neutrino, nor can
it be the result of oscillating to a much more negative massed sterile state with such a large imaginary mass, since the faster than light measurement was for all the recorded particles.
