Thanks for passing by, and the interesting comments/questions.

Sounds like a factor of 5 isn't enough?

We have indeed a factor of 5 between the 1.1 eV and 0.26 eV bounds, but we should keep in mind that those limits are coming from independent experimental probes. What is aimed at KATRIN is to improve the 1.1 eV limit without relying on cosmology. It is always crucial to have independent checks on a given quantity (here the sum of the three light neutrino masses).

You mentioned "some can be massless" in one of our convos before, can 2 of them be massless and just 1 has the mass, or is there no clue yet?

Data is not incompatible with the fact that one neutrino could be massless. For now, only two mass differences have been measured, and there is room for the lightest of the three neutrinos to have a mass compatible with zero. However, this does not allow two neutrinos to be massless.