# Electroweak precision in the future

LEP has measured electroweak precision observables to an extremely good precision ($\sim 0.1\%$). The future linear collider is expected to run far from the W and Z poles so other then higgs and top physics (which are of course very important), I wouldn't expect they'd be able to improve much on any of the measurements that have been done on electroweak observables (e.g., $g, g', v$).

The only other electroweak measurement I am familiar with is muon decay, whose precision could improve in the future. Are there any proposed experiments that would be able to reduce uncertainties on the current measurements of these quantities?

There are several experiments on $\mu$ decay planned, I know of an upgrade of MEG at PSI, who are looking for $\mu \to e \gamma$ and I saw a poster on a new experiment looking for $\mu \to eee$ a while back at a workshop.
Furthermore, there is a so-called $B$-factory collider in Japan, Belle, that is dedicated to electroweak precision and flavor physics by working exactly on the $\Upsilon(4S)$ resonance, which has a large branching fraction to several interesting ($B$)-mesons. There is an upgrade ongoing for Belle's detector which will increase sensitivity in many EWPO in the next few years.
• Thanks for your response. I am aware of the precision flavor violation tests. However, unless I'm mistaken they are not used to improve measurements of electroweak quantities ($g, g' , v$), but instead to constrain FCNC, lepton and baryon number violation, etc. – JeffDror Feb 19 '15 at 13:32