Yay, or something.

 

http://news.bbc.co.uk/2/hi/science/nature/4862112.stm

I just came to this forum after reading the same article just a minute or so before. Nice one but I have not been able to understand how they found it.

I just came to this forum after reading the same article just a minute or so before. Nice one but I have not been able to understand how they found it.

They observed flavour (or flavor) oscillation which can only occur if neutrinos have a mass.

 

I didn't know Standard Model said neutrinos have to have a mass of zero. And this ins't the first experiment showing neutrino flavour oscillation, as indicated in the article there was a similar experiment in 2002.

 

I always thought that neutrinos had a mass... I don't normally think opposite to the Standard Model though. Assuming this observation is correct what kind of impact will this have on the Standard Model?

First of all, this is not really a new (or surprising) result. We have had good evidence for neutrino oscillations (and therefore mass) for some time. This is a confirmation of previous results (albeit with much better precision).

 

Secondly, to say that it is a contradiction of the Standard Model is a little disingenuous. It is a correct statement, since the SM simply has the neutrino masses set to zero, but to build a 'new' Standard Model, with neutrino masses one simply removes the zero mass assumption. There is no inconsistancy in the SM with saying neutrinos have mass (which would not have been the case if, for example, we found the photon had mass).

 

The more interesting question is why are their masses so small? To my mind, this is probably explained by the see-saw mechanism, but that is certainly not clear. And we still have no idea why the top quark is 350,000 times heavier than the electron....