Science Sizes Up 'Ghost Particle'

Using data from the largest ever survey of galaxies, researchers put the mass of a neutrino at no greater than 0.28 electron volts.

This is less than a billionth of the mass of a single hydrogen atom, the scientists say.

The results are to be published in the journal Physical Review Letters and will be presented at the Weizmann UK conference at University College London (UCL) this week.

"Back in 2002, we put an upper limit on the neutrino mass of 1.8 electron volts. So this is an improvement by a factor of six," said co-author Professor Ofer Lahav, from UCL.

It's only an improvement of 6 if the mass is zero and the uncertainty was the same for both measurements.

OK, so they think they know the mass when they don't know how many there are!

I am very sceptical.