
Physicists make most precise measurement ever of the proton's magnetic moment - dnetesn
https://phys.org/news/2017-11-physicists-precise-proton-magnetic-moment.html
======
raverbashing
Doesn't seem to mention how this value agrees or not with predictions

The G-2 experiment at Fermilab is coming online soon and they're investigating
the Muon's magnetic moment, which is suspected to not match the current
predictions

~~~
ISL
Not a prediction, but comparison with previous work:

    
    
      Accepted value [1]: µ = 2.792847351   ± 0.000000009
    
      New value:          µ = 2.79284734462 ± 0.00000000082
    

[1] [http://pdg.lbl.gov/2017/tables/rpp2017-tab-
baryons-N.pdf](http://pdg.lbl.gov/2017/tables/rpp2017-tab-baryons-N.pdf)

~~~
geertj
Nice that the new interval completely lies within the old.

I remember from college that there was an important physical constant where a
new, more precise measurement was pretty far outside the range of the previous
best measurement. I don't remember which one..

~~~
evanb
Depending on when you went to college, you may be thinking of the proton
radius puzzle
[https://en.wikipedia.org/wiki/Proton_radius_puzzle](https://en.wikipedia.org/wiki/Proton_radius_puzzle)
which (to gloss over an enormous amount of detail) amounts to tension between
two different ways of measuring the same property of the proton.

~~~
ISL
Other possibilities: Neutron lifetime, Newton's constant (twice!)

------
titzer
FTA: ...finding it to be 2.79284734462 plus or minus 0.00000000082 nuclear
magnetons...

Ok, physicists can measure this quantity to 10 decimal places and Computer
"Scientists" cannot understand the systems _we built_ well enough to reliably
measure a 1% speedup.

/sigh

~~~
ISL
But you can measure how many bytes are free on a 10 GB disk.

~~~
Filligree
So long you don't care about performance. Sure, "free space" sounds like a
simple concept, but the simple version isn't terribly useful.

