Science Question

[degreen2014]

You know when scientists talk about Muons.
They write Muon-2g
What does 2g stand for.


Much appreciated

[jim360]

it's g-2, rather than -2g, and ...

Muons have a thing called "spin", and "spin" interacts with a magnetic field to make the particle spin around. The strength of that spinning depends on precisely the particle's charge, divided by twice its mass, times some constant. About 100 years ago, when this was first studied, scientists made the prediction that this constant, called "g", should be exactly 2. Later, new calculations showed that it was subtly different from 2. Hence the "g-2", which is to say, "g minus 2", which should be very close to, but not exactly, zero. The remarkable thing is that we think we can make a very precise prediction of this value, and we can also measure it just as precisely, down to just a few hundred parts per billion!

The theory prediction is that g-2 = 0.002331836, and the experiment today gives g-2 = 0.002331841, so the difference is tiny, in the eighth decimal place, but the precision of both is so great that we can make the claim that they really are different and it isn't a calculator error (although stay tuned for updates to this over the next couple of years!)

[Paigntonian]

We will stay tuned. But please try to put things in a simplified way for us non-scientists. I appreciate it's difficult but it would be great to understand these things.

[jim360]

I wasn't trying to complicate things too much there. But if I've messed up in being clear then I apologise. Perhaps you could ask questions about the parts in my post above that you don't understand yet, and I'll have a go at explaining them more clearly.

[Mamyalynne]

Jim has said exactly this but maybe a video will help you Paigntonian.

[Mamyalynne]

Sorry butting in Jim, you weren't there when I started.

[jim360]

No need to apologise, hopefully the video will clear things up! And, if not, I'm still here to answer questions as best I can.

This isn't meant negatively, Paign, but the clearer you are about what you don't get (yet) the easier it is for me to try and explain it. I still think it's a failure on my part not being clear the first time, so really all I'm asking for is the chance to build a conversation, and hopefully we can go from there.