If it was weakly interacting to the extent it would not have interacted
with a particle detector then it would have been seen by now by virtue
of one of many analyses searching for "missing energy" in the detector.


Apparently OPAL searched for this type of effect and didnt find it
(according to wikipedia). I found the paper he

http://www.slac.stanford.edu/spires/...WW&SEQUENCE =

I suspect there will be other analyses that have been done that rely on
missing energy would also be sensitive to production of such a
particle.

Really the onus is on the heim-theorists to tell people specifically
how to search for a neutral electron type particle and to explain why
it wouldnt have been seen already in analyses done, given it has such a
low mass (0.5 MeV).

Yes, the Higgs boson has not been observed. Neither has supersymmetry.
But they do have reasons why we would not have seen them to date in the
theories and they can be tested soon so we can rule them out or
incorpate them into current theories. In the case of the Higgs the
theory assumes the mass is sufficiently lareg we could not have seen it
with the "low" energy experiments we have used so far. But the heim
neutral electron has a very low mass, which is why lots of people are
saying it would have already been seen.

The key points (to my mind) for heim-theory is really it must make
specific predictions that can be tested, it must be consistent with all
experiments performed to date (which means they need to calculate
errors on the predicted masses so we can see the precision they can
calculate them).

Also why dont they show the quark masses in their table? I needs to
have all the particles we know about, because if the calculation fails
for even one particle then the theory does not work as it is.














The measured value is from the PDG group and is usually constructed
from all available measurements to date (but not always).