# Weak Force

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1. Oct 28, 2014

### mokeejoe5

Recently it struck me that I'm not sure I understand the weak interaction at all. What causes it to happen? I know that its mediated by the W and Z bosons and has a short range as a result of the large mass these bosons posses, but what does that range refer to? Range from what?!

2. Oct 28, 2014

### bhobba

Its a predicted by the electroweak theory so your query is - why is the electroweak theory true.

The answer is - we don't know.

That said what is called gauge invariance has shed a lot of light on it, to the point gauge symmetry is considered to lie at the foundation of all the fundamental interactions of the standard model:

The range of a force is a concept from QFT. If the force carrier has zero mass you get an inverse square law like EM and gravity - such is called long range. If they have mass then it falls off quicker than inverse square (if I recall correctly exponentially - but don't hold me to it) and are called short range.

Thanks
Bill

3. Oct 29, 2014

### mokeejoe5

So we don't know what causes it only that it happens? Why assign a range to it then, surely that's meaningless? I ask because I watched a video on YouTube that claimed its caused by bosons inside neutrinos ,when they get within a certain range, interacting with quarks in hadrons, and I was pretty sure that wasn't the case.

4. Oct 29, 2014

### bhobba

Of course we know what causes it - it is explained by the Electroweak theory. What we don't know is why the electroweak theory is true - it just is. However gauge symmetry gives it a very elegant foundation - but the question then is - why is gauge symmetry true - it very elegant and beautiful - which is aesthetically pleasing - but that doesn't tell us why. In science there are always unexplained things. If you explain some thing in terms of other things then all you have done is have a different foundation.

I don't know anything about bosons inside neutrinos etc. It quite possible you have come across some crank claims, but usually cranks don't make videos so I think its just something that was misinterpreted.

Thanks
Bill