On Tuesday, July 27, 2021 at 1:16:03 AM UTC-6, Jonathan Thornburg [remove color- to reply] wrote:
> ... If neutrinos have a nonzero rest mass, special relativity
> requires that they travel slower than light.
Not quite. Imaginary mass would also be nonzero, and there is some indication
that the square of the neutrino mass is negative:
m² = -0.6 ± 2.2 ± 2.1 eV²
C. Kraus et al, \Final results from phase II of the Mainz neutrino mass search in
tritium decay, arXiv:hep-ex/0412056v2 (2005)
m² = -0:67 ± 2:53 eV²
V. N. Aseev et al, \An upper limit on electron antineutrino mass from Troitsk
Interesting that the uncertainty was reduced, but the central value didn't shift
toward the "safety" of positive values, isn't it? And finally we have the preliminary
result from the ongoing KATRIN experiment:
m² = -1.0 + 0.9 - 1.0eV²
Of course, this represents only two-sigma limits, but it's even more interesting.
> But given the known bounds on neutrino masses, the difference between the
> neutrino speed and the speed of light would be too small for the OPERA
> experiment to distinguish.
Yes, the anomalous result could only be possible if the neutrino mass were
HUGE, but we know it's not. It was obvious from the get-go that something
was seriously wrong. Fortunately, the error was discovered and a lot of
other experimental evidence didn't have to be discredited.
But wouldn't it be exciting if KATRIN finds that m² truly is negative? The next
step would be to get some low-energy neutrinos and then REALLY measure